TM
www.aps.org
MARCH • 2013
Written by
Rebecca Thompson, Ph.D.
Illustrated by
Kerry G. Johnson
com
learn how your world works
WELCOME TO PHYSICSQUEST
History of the PhysicsQuest Program
As part of the World Year of Physics 2005 celebration, the American Physical Society (APS Physics) produced PhysicsQuest: The Search for Albert Einstein’s Hidden Treasure. Designed as a resource for middle school science classrooms and clubs, the quest was received enthusiastically
by nearly 10,000 classes during the course of 2005. Feedback indicated that this activity met a
need within the middle school science community for fun and accessible physics material, so the
American Physical Society has decided to continue this program. APS is pleased to present this
eighth kit, PhysicsQuest: Spectra - Turbulent Times.
In the past, each PhysicsQuest kit has followed a mystery-based storyline and requires students to
correctly complete four activities in order to solve the mystery and be eligible for a prize drawing.
For the fourth year in a row students will be following laser superhero Spectra. Past years have
seen the downfall of the evil Miss Alignment (Issue #2), the unfortunate demise of General Relativity (#3) and the evil antics of “mean girl” Tiffany Maxwell’ Demon (#4). This year, the students
will learn about fluid dynamics as they help Spectra try to stop her swim coach Henri Toueaux
from destroying his team in an effort to beat the Thomas A. Edison Middle School Wizards of
Menlo Park, IN in the state swim meet championship.
About the American Physical Society (APS Physics)
APS is the professional society for physicists in the United States. APS works to advance and
disseminate the knowledge of physics through its journals, meetings, public affairs efforts, and
educational programs. Information about APS and its services can be found at www.aps.org.
APS also runs PhysicsCentral, a website aimed at communicating the excitement and importance
of physics to the general public. At this site, www.physicscentral.com, you can find out about APS
educational programs, current physics research, people in physics and more.
TM
PhysicsQuest: Spectra -Turbulent Times!
Written by Rebecca Thompson, Ph.D.
Illustrations by Kerry G. Johnson
PhysicsQuest: Spectra - Turbulent Times! - Issue #5
Published by the American Physical Society
American Physical Society © 2013 – All Rights Reserved
Printed in the U.S.A.
WELCOME TO PHYSICSQUEST
About PhysicsQuest
PhysicsQuest is a set of four activities designed to engage students in scientific inquiry. This year’s
activities are linked together via a storyline and comic book that follows Spectra, a laser super hero
and her battles with “mean girl” Tiffany Maxwell and her impish Demon. Spectra’s super power is her
ability to turn into a laser beam. Her powers are all real things that a laser beam does so in addition
to learning via the 4 activities students will also learn through the comic book.
PhysicsQuest is designed with flexibility in mind – it can be done in one continuous session or split
up over a number of weeks. The activities can be conducted in the classroom or as an extra credit or
science club activity. The challenges can be completed in any order, but to get the correct final result
all of the challenges must be completed correctly.
On Facebook
There’s now a PhysicsQuest Facebook Group, that you may join to connect with other teachers and
participants so that you can share and learn tips and trick.
About the PhysicsQuest Competition
APS sponsors an optional PhysicsQuest competition designed to encourage students to invest in the
project. If you chose to participate in the competition, your class must complete the four activities
and you must submit their answers online by May 17th, 2012. All classes that submit answers online
will receive a certificate of completion and be entered into a prize drawing. Details on the prizes will
be posted on the PhysicsQuest website as they become available.
The online results submission form does not require the answers to all of the questions on the Final
Report. If your class only has time to complete some of the activities, they can still submit their answers, be eligible for prizes and receive a certificate of participation. Each class can only submit one
entry form, so class discussions of results are encouraged.
Answers can be submitted online through the PhysicsQuest website beginning March 25, 2013.
The PhysicsQuest Materials
The PhysicsQuest kit includes this manual and most of the hardware your students need to complete
the activities. There is also a corresponding website, www.physicscentral.com/physicsquest, which
has supplemental material such as extension activities.
The comic book
Each activity will be preceded by several pages of a comic book that will follow the adventures of
Spectra. The comic is also available online. Students will complete the activity and in the end they
will need their answers to all four activities to help Spectra stop the coach from destroying the school.
The Materials List
For more information on these items and where they can be purchased, please visit the PhysicsQuest website. If your kit
is missing any of these materials, please contact Educational Innovations, www.teachersource.com or (203) 229-0730
Included in this kit:
Plastic container and lid
Steel, plastic, wooden spheres
Transparency sheet
Tissue paper
Plastic box
Pipette with rheoscopic fluid concentrate
Black construction paper
Ketchup packets (2)
Glass “sand”
Plastic spoon
Tart pastry pans (4)
Plastic bag
Rubber band
Manual (Comic Book)
Not included in this kit:
Water
Scissors
Paper cups
Bottle with lid (20-ounce soda bottle works best)
Masking tape
Thin book
Permanent markers
Index card
WELCOME TO PHYSICSQUEST
The Teacher Guide includes:
The Student Guide
Each activity has a Student Guide that you will need
to copy and hand out to all of the students.
· Key Terms
This section lists terms related to the activity that the
students will encounter in the Student Guide.
The Student Guide includes:
· Before the Activity:
Students should be familiar with these concepts and
skills before tackling the activity.
· Materials
This section lists the materials students will need for
the activity.
· After the Activity:
By participating in the activity, students are practicing the skills and studying the concepts listed in this
section.
· Getting Started
This section includes discussion questions designed
to get students thinking about the key question, why
it’s important, and how they might find an answer.
· The Science Behind…
This section includes the science behind the activity,
The Student Guide does not include most of this information; it is left to you to decide what to discuss
with your students.
· The Experiment
This section leads students step-by-step through the
set-up and data collection process.
· Key Question: This question highlights the goal of
the activity.
· Safety
This section highlights potential hazards and safety
precautions.
· Materials
This section lists the materials needed for the activity.
Materials that are provided in the kit are in bold type;
you will need to provide the rest.
· Extension Activities
Extension activities related to each activity can be
found on the PhysicsQuest website. This section gives
a brief description of those related to the activity.
· Bibliography and Suggested Resources
This section lists resources used to create this activity
and recommended resources for more information
on the topics covered.
· Key Question
This question highlights the goal of the activity.
· Analyzing your Results
This section leads students through data analysis and
has questions for them to answer based on their results.
PhysicsQuest Website
The PhysicsQuest website, www.physicscentral.com/
physicsquest, has supplemental material for teachers,
such as extension activities. Periodic updates on the
program will also be posted on this site.
PhysicsQuest Logistics
Materials
The PhysicsQuest kit comes with only one set of materials. This means that if your students are working in four small groups (recommended), all groups
should work simultaneously on different activities
and then rotate activities, unless you provide additional materials. The Materials List on the PhysicsQuest website includes specific descriptions of the
materials and where they can be purchased. All materials can be reused.
Safety
While following the precautions in this guide can
help teachers foster inquiry in a safe way, no manual
could ever predict all of the problems that might occur. Good supervision and common sense are always
needed. Activity-specific safety notices are included
in the Teacher Guide when appropriate.
WELCOME TO PHYSICSQUEST
Time Required
The time required to complete the PhysicsQuest activities will depend on your students and their lab
experience. Most groups will be able to complete one
activity in about 45-minutes.
Small Groups
Working effectively in a group is one of the most important parts of scientific inquiry. If working in small
groups is challenging for your students, you might
consider adopting a group work model such as the
one presented here.
Group Work Model
Give each student one of the following roles. You
may want to have them rotate roles for each activity
so they can try many different jobs.
· Lab Director
Coordinates the group and keeps students on task.
· Chief Experimenter
Sets up the equipment and makes sure the procedures are carried out correctly.
· Measurement Officer
Monitors data collection and determines the values
for each measurement.
· Report Writer
Records the results and makes sure all of the questions in the Student Guide are answered.
· Equipment Manager
Collects all equipment needed for the experiment.
Makes sure equipment is returned at the end of the
class period and that the lab space is clean before
group members leave.
PhysicsQuest in the Classroom
This section suggests ways to use PhysicsQuest in
the classroom. Since logistics and goals vary across
schools, please read through the suggestions and
then decide how best to use PhysicsQuest. Feel free
to be creative!
· PhysicsQuest as a stand-alone activity
PhysicsQuest is designed to be self-contained – it can
be easily done as a special project during the day(s)
following a test, immediately preceding/following
winter break, or other such times. PhysicsQuest also
works well as a science club activity and extra credit
opportunity.
· PhysicsQuest as a fully integrated part of regular
curriculum
The topics covered in PhysicsQuest are covered in
many physical science classes, so you might have students do the PhysicsQuest activities during the corresponding units.
· PhysicsQuest as an all-school activity
Some schools set up PhysicsQuest activity stations
around the school gym for one afternoon. Then small
groups of students work through the stations at assigned times.
· PhysicsQuest as a mentoring activity
Some teachers have used PhysicsQuest as an opportunity for older students to mentor younger students.
In this case, 8th or 9th grade classes first complete
the activities themselves, and then go into 6th or 7th
grade classrooms and help students with the activities.
PUBLISHED BY THE AMERICAN PHYSICAL SOCIETY © 2013
TURBULENT TIMES
Written by Rebecca Thompson, PH.D. • Illustrated by Kerry G. Johnson
Everything has calmed down at Nikola Telsa Middle School for Lucy “Spectra” Hene and
her friends since their adventure with Tiffany Maxwell and her Demon in Issue #4. Over the last few
months, Lucy has managed to focus on her training with the swim team. We start this tale with Lucy
and her swimmates training at the Rose Bowl Aquatic Center in Pasadena, California.
C’MON CHARGERS!
GET BACK IN THE WATEr!
YOU’VE GOT one more set.
AFTER THAT, You ALL GET
to cool down.
You’ve ALL worked hard,
but this one is going to
be rough. ARE you ready?
AWHH COACH! WE’RE TIRED!
CAN WE TAKE A BREAK?
A-C! A-C! POWER LINES!
TESLA BEATS YOU
EVERY TIME!
GO CHARGERS!
I THOUGHT I WAS TRAINING
WINNERS, NoT WHINERS!
Remember, every time you whine,
that’s another 100 METERS
added to your “whining” set.
NOW GET READY.
3... 2... 1...
SPLOSH ! !
THAT WASN’T
GooD ENOUGH!
EVERYBODY, Make
sure when you’re
underwater, you look
more like an airplane
wing than a barge.
BACK AT SCHooL
I Know
GenERAL RELATIVITY*
did an experiment
in PHYSICS class
ON THIS TOPIC.
*General Leslie J. Relativity first
appeared in Spectra #3: Force.
THAT SET HURT!
I sure FELT like a barge,
CERTAINLY not LIKE
an airplane wing.
THAT just
dIDN’t feel
right And
my shoulders
are
KILLING ME.
IT’s Easier for
water to flow
around a triangle
than a square,
so FORM yourself
InTO a triangle.
GO AGAIN.
3 ... 2 ... 1 ...
Lucy’s already exhausted, but she and
the rest of the team manage to push
themselves off the wall.
MINE Too, it’s like
the water WAS being
pushed back
against us.
This year’s team is
great. I think we
CAN WIN IT ALL!
Back at the team’s hotel
I just need to
push them a
little harder.
AS THE SWIM TEAM
MANAGER YOU KNoW
I HAVE TO KeeP UP WITH
EVERYONE’s TIMES. WHAT was
UP WITH THAT LAST SET?
WHY DID YOU GUYS
SLOW DOWN ON
THOSE LAST LAPS?
MAYBE WE CAN TALk
THROUGH THIS STUFF
AFTER YOU STOP
CHOMPING DOWN ALL
THAT JUNK FooD.
PHYSICSQUEST: SPECTRA - TURBULENT TIMES (ISSUE #5)
ACTIVITY 1 - A
TEACHER GUIDE
ACTIVITY 1: Go With the Flow
NOTE: Setting up this experiment can take a bit of time. If you have limited class time, set this up activity beforehand.
INTRO
You often see water flowing, but it is difficult to see how it
flows. This experiment uses “rheoscopic fluid” to show how
water flows around different shapes.
KEy TERMS
Fluid: Anything that flows; both liquids and gases are fluids.
Rheoscopic fluid: A type of liquid that has tiny, ground-up
fish scales suspended in water.
Flow: Movement of a fluid
Laminar (streamline or smooth) Flow: Fluid flows in one
direction and doesn’t mix side to side
Turbulent (rough) Flow: As the fluid flows it mixes from
side to side and can also create eddies
Hydrodynamic: How well a fluid flows by an object. If
something is extremely hydrodynamic, fluid flows by it easily.
Eddy: Swirls and mixing that happens when fluid flow is interrupted by an object. If an object isn’t very hydrodynamic,
lots of eddies are formed.
MATERIALS
n Pen box top
n Pipette filled with rheoscopic fluid
n Black construction paper
n Transparency
n Sheet with rectangles
n * Bottle with lid (20 ounce soda bottle works well)
n * Cup
n * Adhesive tape
n * Thin book
n * Water
n * Permanent Marker
n * Scissors
*Not included in the PhysicsQuest Kit
BEFORE THE ACTIVITY, STUDENT
SHOULD KNOW
n Fluids flow downhill.
n The flow of a fluid changes when it encounters an object.
n The shape of the object will affect how the flow changes.
n Periodic motion means an object follows the same path
repeatedly.
KEY QUESTION
Which shapes are
more hydrodynamic?
AFTER THE ACTIVITY, STUDENTS
SHOULD BE ABLE TO
n Define “laminar flow.”
n List the shapes that allow water to easily flow and the
shapes that are more difficult.
n Explain why “hydrodynamic” object such as boats are
shaped as they are.
n Explain why Michael Phelps works on his streamline.
THE SCIENCE BEHIND flowing
around an object
If you’ve ever stuck your hand out of the window of a moving car or watched Michael Phelps streamline underwater on his way to win yet another gold medal, you already
know a lot about how fluids flow. Think of a the shape of
a Honda Element vs. a Corvette. Which one do you think
moves through air more easily? You were probably able to
answer these questions pretty quickly because we all have an
intuitive understanding of how water and air flow. In this experiment you will get to see what happens when fluid flows
around differently shaped objects.
Most times when water is flowing it is difficult to see exactly
how it is flowing. However, it is possible to see how water
flows using a special type of fluid called rheoscopic fluid.
Rheoscopic literally means “current showing.” It is made up
of tiny, shiny flat pieces that are good reflectors of light. Because they are flat, the will point in the direction of the water
(Fig. 1). They don’t mix with water the way dyes might so
the fluid can be used over and over again. Often times these
shiny pieces are made of ground up fish scales.
Water moves the most quickly if there is nothing in its way.
When its flowing smoothly, or laminar flow, all the water
is flowing in the same direction with no turbulence. If the
water is flowing along and runs into an object, it’s going to
slow down in order to flow around the object somehow. If
the object doesn’t create much turbulence and the water is
still flowing pretty smoothly, it’s not going to slow down
too much. It doesn’t lose a lot of energy to eddies and so can
keep going at roughly the same speed and it will still be close
to laminar flow.
PHYSICSQUEST: SPECTRA - TURBULENT TIMES (ISSUE #5)
ACTIVITY 1 - B
TEACHER GUIDE
ACTIVITY 1: Go With the Flow
NOTE: Setting up this experiment can take a bit of time. If you have limited class time, set this up activity beforehand.
However, if the object creates a lot of eddies and turbulence, then the water is going to slow down a lot. Its flow
will no longer be anywhere near laminar flow. The closer
flow is to laminar, the faster it can go.
The opposite is also true. If you are trying to drag something through water and it doesn’t create many eddies,
then it doesn’t require a lot of energy to move it through
water quickly. But, if it makes the water really rough, you
are going to have to push it harder to get it through. So if
you can figure out how much an object disrupts a fluid’s
flow, you can figure out how easy it would be to push
through water.
This experiment does just that by slowly pouring rheoscopic fluid down a ramp and having it pass by objects
of different shapes. It is easy to see which shapes cause
the most turbulence and which cause the least. Because
shapes that cause the least turbulence move through water
the easiest, they are the most hydrodynamic.
A quick note or two about this experiment: First, it can be
tricky to get the water to flow smoothly, so it is important
for the students to pour the water very slowly. If there is
anything such as a rough piece of tape in the bottom of the
ramp, it will cause its own turbulence and throw things
off. Second, there are several variations of this on the web,
the most common of which is to put blocks in a dish and
use some sort of spatula type device to “push” the water
to make it flow. I have no idea who wrote this or why it is
so prevalent, but it just doesn’t work. When the water is
“pushed” there are too many eddies created by the movement of the side of the spatula for the experiment to be of
any use. The PhysicsQuest version of this experiment may
seem a little fussy, but it requires all this to make sure the
kids can actually see the effect.
SAFETY
Review these guidelines closely with students before the
activity and outline consequences for failure to follow
them! Rheoscopic fluid, while not poisonous, is not tasty
and could stain. Make sure students do not drink or splash
the rheoscopic fluid.
Corresponding Extension
Activities
n Coanda Effect 1 and 2
n Spoon lift
n Laminar flow
Bibliography/Suggested Resources
n http://swimright23.webs.com/streamline.htm (scary math but great pictures)
n http://www.physicscentral.com/explore/pictures/turbulence.cfm
n http://gizmodo.com/5925135/the-worlds-most-aerodynamic-triathlon-bike-even-has-streamlined-snack-storage
(The lack of turbulence in the “airplane wing” shape is also used in high performance bikes.
This article is a good explanation of why.)
Figure 1
Water
Pipe
Movement of fluid
Flap
Tiny, flat shiny pieces
PHYSICSQUEST: SPECTRA - TURBULENT TIMES (ISSUE #5)
ACTIVITY 1 - C
STUDENT GUIDE
ACTIVITY 1: Go With the Flow
NOTE: Setting up this experiment can take a bit of time. If you have limited class time, set this up activity beforehand.
INTRO
Why can Olympic swimmers Michael Phelps go
faster than Ryan Lochte (most of the time)? Why
are the hulls of boats shaped like they are? In this
experiment you will use some shiny (and slightly
smelly) stuff called “rheoscopic fluid” to see how
water flows around different shapes
KEY QUESTION
Which shapes are
more hydrodynamic?
MATERIALS
n Pen box top
n Pipette filled with rheoscopic fluid
n Black construction paper
n Transparency
n Sheet with rectangles
n * Bottle with lid (20oz soda bottle works well)
n * Cup
n * Adhesive tape
n * Thin book
n * Water
n * Permanent Marker
n * Scissors
*Not included in the PhysicsQuest Kit
SETTING UP THE EXPERIMENT
GETTING STARTED
n Cylinder (Fig. 1):
Roll the rectangle into a cylinder about half an
inch in diameter. There will be some overlap.
Tape the seams shut, both the inside and the outside, making sure the tape lays very flat.
When you stick your hand out of a car window, does
air rush by it more easily when your hand is vertical or horizontal? ___________________________
_________________________________________
How is the front of a barge different than the front of
a speed boat? Which do you think is faster?
_________________________________________
What is an eddy? Turbulence? ________________
_________________________________________
_________________________________________
____________
Can you think of times you’ve seen water flow
smoothly? Roughly? White water? ____________
_________________________________________
_________________________________________
_________________________________________
When Michael Phelps cuts through the water, particularly when he is underwater, what shape does he
make his body? ____________________________
_________________________________________
THIS PART CAN BE TRICKY. FOLLOW THE
INSTRUCTIONS CAREFULLY
1. Place the transparency film over the sheet of
paper with the rectangles and trace them with a
permanent marker.
2. Cut out the rectangles from the transparency
film. Make sure you note which rectangle is for
which shape.
3. When taping them together, it is important that
the tape lay very flat.
n Triangle (Fig. 2):
1. Fold the rectangle along the dotted lines, making very sharp edges.
2. Fold into a triangle, two of the flaps will overlap.
3. Tape, being careful to flatten the tape.
n Square (Fig. 2):
1. Roll the rectangle into a cylinder with the
short edges just touching. Be careful not to overlap.
2. Make creases along the dotted lines.
3. It should naturally form a square.
n Wing (Fig. 4):
Pinch together the ends so that the two ends
are touching, Tape them together using a loop
of tape on the inside. You should now have a
teardrop shape.
PHYSICSQUEST: SPECTRA - TURBULENT TIMES (ISSUE #5)
ACTIVITY 1 - D
STUDENT GUIDE
ACTIVITY 1: Go With the Flow
NOTE: Setting up this experiment can take a bit of time. If you have limited class time, set this up activity beforehand.
SETTING UP THE RAMP
1. Cut the black construction paper the same size
as the bottom of the box and tape it to the outside
of the box. This is so that it is easy to see the
rheoscopic fluid as it flows through the box.
4. Place the square in the middle of the ramp (Fig.
2) and again pour the fluid down the ramp. You
may need to hold it down with your finger, but
be careful not to stick your finger in the moving fluid, this will royally screw up your results.
Draw what you see:
2. Cut one of the short ends of the box to make
a flap.
3. Tape a cup to the side of a desk. Use lots of
tape. It needs to be well stuck on the desk..
4. Put the box on the desk with the flap pointing into the cup and put the other end on the thin
book to elevate it. You should have created a
ramp for the fluid to flow down and into the cup.
(Fig. 5)
Look at the shapes you created. Which do you
think will allow the water to flow past with the
least turbulence? If something can pass through
water with little turbulence, it is said to be “hydrodynamic.” Predict which shapes will be the
most hydrodynamic and line up the shapes in
front of you from what you think will be most
hydrodynamic to least hydrodynamic.
ANALYZING YOUR RESULTS
1. Fill the free cup with rheoscopic fluid.
2. Very slowly pour the fluid from the cup into
the top of the ramp. Draw what you see.
5. Repeat with the other shapes, each time drawing what you see.
CIRCLE
______________________________________
______________________________________
______________________________________
TRIANGLE
______________________________________
______________________________________
______________________________________
WING
3. Now the cup taped to the table is full. Remove
it and tape the empty cup to the table.
______________________________________
______________________________________
______________________________________
PHYSICSQUEST: SPECTRA - TURBULENT TIMES (ISSUE #5)
ACTIVITY 1 - E
STUDENT GUIDE
ACTIVITY 1: Go With the Flow
NOTE: Setting up this experiment can take a bit of time. If you have limited class time, set this up activity beforehand.
1. What did it look like as the fluid was flowing without
a shape in the way? How was it moving? When something is flowing in a straight line without any turbulence, it is called “laminar flow.”
___________________________________________
___________________________________________
___________________________________________
___________________________________________
2. What happened when it ran into one of the shapes?
Did its movement change?
___________________________________________
___________________________________________
___________________________________________
___________________________________________
5. How do you think the turbulence the shape creates
in water affects how fast it might move through water?
___________________________________________
___________________________________________
___________________________________________
___________________________________________
6. What does it mean to be “hydrodynamic”?
___________________________________________
___________________________________________
___________________________________________
___________________________________________
3. What shapes created the most turbulence? What
shapes created the least?
7. Why do you think Michael Phelps “streamlines” underwater to get ahead of the competition?
___________________________________________
___________________________________________
___________________________________________
___________________________________________
___________________________________________
___________________________________________
___________________________________________
___________________________________________
4. Think about what would happen if the shape was
moving through the water instead of the water moving
by the shape. Which ones do you think would move
through the most quickly?
___________________________________________
___________________________________________
___________________________________________
___________________________________________
Rank the shapes in order from most hydrodynamic to
least hydrodynamic.
1.______
2.______
3.______
4.______
USe YOUR RESULTS TO HELP SPECTRA FIND THE CAFETERIA
What was your ranking of most hydrodynamic to least hydrodynamic
1. Wing, circle, triangle, square (The gang should go straight.)
2. Square, circle, triangle, wing (The gang should turn left.)
3. Circle, square, wing, triangle (The gang should turn right.)
PHYSICSQUEST: SPECTRA - TURBULENT TIMES (ISSUE #5)
ACTIVITY 1 - F
STUDENT GUIDE
ACTIVITY 1: Go With the Flow
NOTE: Setting up this experiment can take a bit of time. If you have limited class time, set this up activity beforehand.
TRIANGLE
Figure 5
Figure 3
Figure 4
WING
Figure 2
SQUARE
Figure 1
CYLINDER
Shape templates
Water
Tiny, flat shiny pieces
Movement of fluid
NOTE: Images not to scale
I don’t know how
to describe WHAT
HAPPENED. but it seemed
like I was swimming
upstream
AGAINST
THE CURRENT.
RUBY, I WORKED
reaLLy hard to swim.
but AFTER LooKING AT
THoSE TIMES, IT looks
like I was going
pretty slow.
WeLL, i don’t know
Alright CRYBABIES,
I’m going to the
boardwalk to have
SOME fun. You CAN join
me if you WISH, but
don’t act like
YOU know me,
I DO HAVE AN
IMAGE TO
UPHOLD.
about you, “Hobbit”.
but “I” was going
plenty fast.
LUCy, Don’t woRRy
too much,
everyone
was slow.
By Amy Flatten.com
I’mNOT
NOTAACRyBABY!
CRyBABY!
I’m
BUT
THE
BOARDWALK
SOUNDS
BUT THE BOARWALK SOUNDS
better
than
sitting
AROUND
here.
better than sitting AROUND
something
isn’t
right
and
maybe
here. something isn’t right
FRESH
AIR
will AIR
and SOME
maybe
SOME
FRESH
usus
FIGURE
IT IT
OUT.
wiLLhelp
help
FIGURE
OUT.
TIFFANY,, WAIT
WAIT FOR
FOR US.
TIFFANY
US.
A few minutes later, the adventurous
girls explore the city’s popular
beaches and Boardwalk District.
STOP POINTING THAT
CAMERA PHONE THIS WAY!
I’M NOT IN THE MooD TO
See MY FACE UPLOADED
TO INSTAGRAM.
Oh, C’MON!
C’MON! STOP
STOPPING
Oh,
BEING
BEING
I’LL make
SILLY!SILLY!
I’ll make
sure
sure
you
look
good.
you
look
good.
Don’t
Don’t you
you trust
trust
my
skiLLs?
my skills?
HEY LUCY,
LooK OVER THERE.
is that who I think
it is And what’s
going on with THOSE
waves? That’s
JUST not right.
Lucy and Ruby can’t believe their eyes. It’s their
swim coach and it looks like he’s controlling
the water’s movement. Ruby’s “investigative blogger” instincts take over as she
continues snapping photos with her
camera phone.
The sunset
is beautiful. I love
being out here and
seeing these waves,
The lighting is perfect.
NOW, JUST SMILE.
PHYSICSQUEST: SPECTRA - TURBULENT TIMES (ISSUE #5)
ACTIVITY 2 - A
TEACHER GUIDE
ACTIVITY 2: Shaken, not Stirred
.
INTRO
If you’ve ever gotten a can of mixed nuts, you may have
noticed that the Brazil nuts most often end up at the
top. It’s not the way they are packed that makes this
happen; it’s actually physics. More specifically, it’s an
effect that scientists, not without a love of snack food,
have named “The Brazil Nut Effect.” You’d think that
when things are shaken together, they’d mix but often
they separate instead. In this experiment we’ll see what
makes shaken things separate and how. This experiment
is easy to do, doesn’t require a lot of big, fancy physics
words, but it is surprising and awesome.
KEy TERMS
Density: The amount of mass per volume. Metal is
more dense than plastic.
Granular material: Any group of grains. Gumballs
and sand are examples of granular materials.
Convection: Any movement of a group of molecules
in a fluid. The most common example is convection
caused by heating.
Granular convection: Motion of grains (as opposed to
molecules) due to shaking. It is very similar to liquid
convection.
MATERIALS
n
n
n
n
n
n
Clear plastic container with lid
Plastic (yellow or green) spheres
Metal spheres
Wooden spheres
* Adhesive tape
*Cup
* Not included in the PhysicsQuest Kit
BEFORE THE ACTIVITY, STUDENT
SHOULD KNOW
n Metal is more dense than plastic.
n Wood and plastic have similar densities.
n The definition of convection
AFTER THE ACTIVITY STUDENTS
SHOULD BE ABLE TO
n Say what happens when particles of different sizes
are shaken together
n Say what happens when particles that are the same
size but different masses are shaken together
n Explain what is meant by the “Brazil Nut Effect.”
KEY QUESTION
How do density and size affect how
spheres mix when they are shaken?
THE SCIENCE BEHIND SHAKEN,
NOT STIRRED
Though they no longer put prizes in cereal boxes, I’m
guessing that as a kid, most of us had them. And most
of us also had the experience of either having to wait
till the box was almost empty to get the prize or having
to open the box from the bottom. And, if you’ve ever
had the experience of being late for a party and grabbing a can of mixed nuts as your food contribution, you
know that the Brazil nuts always end up on top. You can
blame physics for both. Physics apologizes for the cereal box toy thing. But why is this happening? Usually
we shake things to mix them, such as salad dressing or a
good martini. However, systems made of “grains,” such
as cans of nuts and boxes of Cap’n Crunch Berries cereal, behave differently than either solids or liquid and
there is a whole branch of physics devoted to studying
them called granular materials. It’s an extremely important field of physics, particularly for manufacturing
things like gumballs and pharmaceuticals in pill form.
If candy needs to be mixed or separated, it’s important
to know the physics involved.
Grains are a weird type of system, made up of solids
you can see but often behaving like a liquid. In fact,
a lot of terms used for liquids, such as convection and
flow are also used for granular materials.
Think about what makes a liquid a liquid. The molecules can move around easily, they aren’t in any particular order and there is a lot of space between them.
When a group of grains in a container is shaken, it can
be thought of as a “liquid” because it has the same properties. The grains can move around easily, they aren’t
in any particular order and there is a lot of space between them. Shake them even harder and they become
a granular gas. And just like liquids and gases, they undergo convection. Granular convection is not driven by
heat as it usually is in liquids and gases. Rather, it is
driven by vibration and friction between the grains and
the walls of their containers. This activity has two experiments that look at how the grain’s density and size
affect how they move around in these granular liquids
and gases (Fig. 1).
PHYSICSQUEST: SPECTRA - TURBULENT TIMES (ISSUE #5)
ACTIVITY 2 - B
TEACHER GUIDE
ACTIVITY 2: Shaken, not Stirred
The first experiment involves a whole lot of tiny
plastic spheres and about 3 larger wooden spheres.
When the container is shaken, the energy of the shaking causes the grains to rise, but the grains next to
the container wall can’t jump up as far because of the
friction with the walls.
As the spheres keep moving up the middle they
slowly push down the spheres on the side and a convection current is set up. The larger wooden spheres
that started out on the bottom get pushed up with this
convection current too. Unlike the rest of the spheres,
though, they get stuck at the top. When the container
is shaken, it adds a lot of space between the grains,
but the spaces are still smaller than the size of the
wooden spheres. Once they are at the top, they can’t
fit back into the granular convection current. The get
stuck there as all the smaller spheres fill in below
them. This is called the Brazil Nut Effect (Fig. 2).
The second experiment involves spheres of the same
size but different densities. In this experiment the container is shaken at an angle instead of up and down.
Because it is at an angle the convection currents are
set up as before. When the container is shaken the
grains have a lot of space between them and still have
gravity pulling them towards the floor. They can be
seen as a “granular liquid.” In fact, if the container
was a lot bigger and you shook them really hard, they
might actually even be a granular gas. The grains do
exactly what we know all liquids do, they separate
out based on density. The heavier metal spheres go to
the bottom and the lighter plastic spheres move to the
top. It is neat to try this experiment while holding the
container straight up and down. You can watch the
metal spheres in the sea of plastic and see the convection currents being set up (Fig. 3). Grains can be
so interesting because they just don’t quite fit in any
of the standard categories of states of matter, but are
everywhere. The physics of grains can save you from
an avalanche, separate gummy bears from gumballs
and tell you how to build a salt storage silo. These are
just two fun granular experiments but there are many,
many more you can find and try out. Personally, I
think this is one of the neatest branches of physics.
SAFETY
Review these guidelines closely with students before
the activity and outline consequences for failure to
follow them! Do not ingest the spheres. They are
a choking hazard. Though this is called the Brazil
Nut Experiment, nothing is actually edible. Always
closely monitor students as they experiment with the
spheres.
Corresponding Extension
Activities
n Shock Absorbent Sand
n Angle of Repose
n Density Ball Sorting
Bibliography/Suggested Resources
n http://io9.com/5786442/the-brazil-nut-effect-why-the-biggest-nuts-rise-to-the-top
n http://www.null-hypothesis.co.uk/article/1303
n http://physicsworld.com/cws/article/news/2001/apr/11/cracking-the-brazil-nut-problem
n http://www.wildsnow.com/520/the-brazil-nut-effect-how-to-survive-an-avalanche/
Figure 1
Direction
to shake
Figure 2
.
Figure 3
PHYSICSQUEST: SPECTRA - TURBULENT TIMES (ISSUE #5)
ACTIVITY 2 - C
STUDENT GUIDE
ACTIVITY 2: Shaken, not Stirred
INTRO
If you’ve ever gotten a can of mixed nuts, you may have
noticed that the Brazil nuts end up at the top most often. It’s not the way they are packed that makes this
happen, it’s actually physics. More specifically it’s an
effect that scientists, not without a love of snack food,
have named, “The Brazil Nut Effect.” You’d think that
when things are shaken together, they’d mix but often
they separate instead. In this experiment we’ll see what
makes shaken things separate and how. This experiment
is easy to do, doesn’t require a lot of big, fancy physics
words, but is surprising and awesome.
KEy TERMS
Density: The amount of mass per volume. Metal is
more dense than plastic.
Granular material: Any group of grains. Gumballs
and sand are examples of granular materials.
Convection: Any movement of a group of molecules
in a fluid. The most common example is convection
caused by heating.
Granular convection: Motion of grains (as opposed to
molecules) due to shaking. It is very similar to liquid
convection.
MATERIALS
n
n
n
n
n
n
Clear plastic container with lid
Plastic (yellow or green) spheres
Metal spheres
Wooden spheres
* Adhesive Tape
*Cup
* Not included in the PhysicsQuest Kit
GETTING STARTED
1. What do you think happens when you have a
bunch of spheres, such as gumballs or beads in a
container and shake it. Do they mix? Do they move
around in any particular way? _________________
_________________________________________
_________________________________________
2. If you could see the molecules of gases and
liquids, what do you think they would look like?
Would they be spread out or close together? Would
they be moving?
_________________________________________
_________________________________________
_________________________________________
.
KEY QUESTION
How do density and size affect how
spheres mix when they are shaken?
3. If you had liquids of two different densities in the
same cup, what would happen?
________________________________________
________________________________________
________________________________________
SETTING UP THE EXPERIMENT
You will be doing two separate experiments. In the first
one, you will see what happens when spheres of two
different sizes but the same density are mixed together
and then shaken. In the second you will investigate
what happens when you do the same thing with spheres
of the same size but different densities.
n Experiment 1:
1. Put the wooden spheres in the bottom of the container and then pour the plastic spheres on top.
2. Put the lid on and seal with a strip of tape.
3. What do you think will happen to the wooden
spheres when you shake the container? __________
_________________________________________
Figure 1
4. Shake the container up and
down roughly 20 times. Make
sure the bottom is horizontal and
that you are shaking it directly up
and down. Watch what happens to Direction
to shake
the wooden spheres as you shake
the container (Fig. 1). Are they
moving? How? Record the number
of wooden spheres on the top and bottom of the container.
Top_______
Bottom______
5. Turn the container over so that the lid is now facing down and the bottom is now the top (good thing
you taped the lid on!). Repeat the experiment and
again write down the number of spheres on the top
and bottom (the lid side is now the bottom).
Top_______
Bottom______
6. Do this a few more times and average your results.
7. Top Average________
Bottom Average_______
PHYSICSQUEST: SPECTRA - TURBULENT TIMES (ISSUE #5)
ACTIVITY 2 - D
STUDENT GUIDE
ACTIVITY 2: Shaken, not Stirred
2. Did they move up the middle or up the sides?
How did the plastic spheres move?
_____________________________________
_____________________________________
_____________________________________
___________________________
n Experiment 2:
1. Remove the wooden spheres from the
container and dump the plastic spheres
into the cup.
2. Add the metal spheres to the cup and use
your hand to mix them around till they are
well mixed. Don’t shake! Use your hand
to mix them.
3. Pour the mixture of spheres into the container and again tape the lid on (Fig. 2).
.
3. Do you think the spheres are more like the
molecules in a solid, liquid or gas when they
are shaken?
_____________________________________
______________________________________________
______________________________________________
_________
Direction
to shake
Figure 2
4. Hold the container at a slight angle and shake vigorously for several seconds. What is happening to the
metal spheres as you are shaking? Are they moving?
How? ______________________________________
___________________________________________
___________________________________________
____________________________________________
5. Count the number of metal spheres you see at the
bottom and the number at the top.
Top_______ Bottom________
n Experiment 2:
1. How did wooden spheres behave when the container
was shaken? Was this what you thought would happen?
______________________________________________
______________________________________________
______________________________________________
5. Turn the container over and repeat the experiment.
Top____ Bottom____
Did they move up the middle or up the sides? How did the
plastic spheres move?
______________________________________________
______________________________________________
______________________________________________
6. Repeat the experiment several more times and average your results
Do you think the spheres are more like the molecules in a
solid, liquid or gas when they are shaken?
Top Average____ Bottom Average____
______________________________________________
______________________________________________
______________________________________________
ANALYZING YOUR RESULTS
n Experiment 1:
1. How did the wooden spheres behave when the container
was shaken? Was this what you thought would happen?
______________________________________________
______________________________________________
______________________________________________
What happens when you have a liquid with two different
densities? How does this compare to the shaken spheres?
______________________________________________
______________________________________________
______________________________________________
Using your results to help Spectra and HER FRIENDS find the kitchen
What happens when the container is shaken?
n The wooden spheres and the metal spheres rise to the top _____________________ (The gang should go straight.)
n The wooden spheres sink and the metal spheres rise
________________________ (The gang should go left.)
n The metal spheres sink and the wooden spheres rise ________________________ (The gang should go right.)
They head down
They
down to
to the
thebeach,
beach,
and try not to
and
to be
be seen
seenby
by
Coach Henri
Henri Toueaux.
Toueaux.
coach
WHOA! that’s definitely
not normal. THE Waves ARE crashING
onto the beach not away from it.
But how can COACH be doing that?
it’s against the
laws of physics!
LUCY, you turn into
a laser. I don’t think
you’RE the one to say
superpowers
aren’t possible.
I have no idea HOW I’M
MAKING THIS HAPPEN, BUT
WOW, THIS IS AMAZING!
Water can do whatever
I teLL it to DO. Not only is
THIS fun, it’s a great way
to train the SWIM team.
We’re definitely going to
beat THAT THOMAS A. Edison
Middle School AT THE MeeT
this year!
Point taken!
JUST KeeP TAKING
THE PHOTOS.
unless there
are reaLLy HYPER
dolphins out there!
It reaLLy looks
like COACH
IS making
the water dance
Look at the way
it flows, twists
and catches
the moonlight.
It’s BEAUTIFUL!
GET BACK!
HE’S LooKING THIS WAY.
I don’t want him to
see us. Let’s get out
of here.
WE have to WIN!
They can’t win again, I wiLL
be the laughing stock of
Sequoia University
QUIckie Coaching School.
I always come in
second, but not this year.
Not with this power!
The championship WILL BE mine!
Mine I say!
????
The
next
day, the
swim
team
flies
In
the
morning,
the
swim
team
backback
home.
Still confused
at
flies
home.
Still confused
what
they
saw
last
night,
neither
at
what
they
saw
last
night,
Lucy
LucyRuby
nor Ruby
mentions
to the
nor
mention
it to theit coach
Coach
or theswimmers.
other swimmers.
or
the other
Back at Nikola Tesla Junior High School
WELCOME BACK!
how was the
training IN CALI?
you HARDLY SENT
ME ANY TEXT
MEssAGES.
I was woRRied.
Later
Laterthat
thatday,
day,the
thefriends
friendsmeet
meetup
up
atatthe
thePizza
PizzaJoint.
Joint.They
Theytell
tellthe
theguys
guys
about
aboutthe
theCoach’s
coach’salleged
allegedpowers.
powers.
See LUCY, you look
great in that pic.
THAT’s Definitely
a profile
PHOTO.
it’s bluRRy, BUT
LooK AT THIs one,
I don’t know if that’s
water going the
wrong way or just
a smudge.
WeLL, it’s not convincing
at aLL. Maybe it was nothing.
And even if it was something,
maybe it doesn’t matter,
it’s not like he was
hurting anyone.
KAS, It was brutal!
I’VE never swum so hard
in my life. It FELT LIKE
the water was fighting
AGAINST me WITH EACH LAP.
Let’s meet up
after school;
bring Gordy.
Ruby AND I WILL
FILL you in.
Ruby, PLEASE focus!
We’re trying to see if
you got a picture of
Coach moving water
and hopefuLLy WE can
figure out how
HE DOES IT.
If we have
a picture, we
can prove it
if we need to.
Super powers are never
nothing. Maybe that’s why
we had to work twice as
hard at SWIM practice.
If I were a coach and I
wanted my team to BE FIT
AND work harder, I’d USE
ANYTHING NECEssARY WITH
THE WATER TO make them
work harder!
HIS “POWER” WAS hurting
people. The whole team
is on the verge of
being injured OR Worst!
I DON’T KNOW! I just know
that a coach who has
superpowers and an
unswerving desire to
win is never a good
combination.
Lucy, You aren’t
being very
helpful. It’s not
like we know he’s
going to do
anything.
So far there
have been
surprisingly
few threats
to take over
the world or kiLL
us aLL. He just
splashes WATER
AROUND. what exactly
do you want us to do?
He’s losing his mind
and I’m woRRied we wiLL aLL
be in the way. Just promise
me you wiLL be at the swim
meet this Friday and keep
an eye out for
anything odd.
Ok, OK, calm down.
we HAD PLANNED TO BE THERE ANYWAY.
NOW WE’LL BE on the lookout
FOR ANYTHING STRANGE.
Friday’s State Championship Swim Meet
features the Nikola Tesla Junior High School
Chargers vs. the Thomas A. Edison Middle
School Wizards. The schools have a long
running and competitive rivalry.
THANKS
GUYS!
*To find out why Nikola Tesla believes Thomas Edison owes him $50,000; see PhysicsQuest 2008 Nikola Tesla and the Electric Fair
COACH, YOU WORKED
US SO HARD AT
PRACTICE THAT ALL OUR
SHOULDERS AND LEGS ARE
ACHING! I CAN
BARELY SWIM!
CHARGERS!
I’M NOT HAPPY!
LooK AT THAT SCORE.
WHY ARE WE TIED WITH
THOSE WIZARDS!
STOP MAKING
EXCUSES, LUCY.
GET READY FOR
THE NEXT RACE!
AND JUST TO MAKE CERTAIN OF
VICTORY, I WILL BE TO USING MY
“SPECIAL” GIFT ...
TO WIN
IT ALL!
THE SCORE IS
TIED BECAUSE OF
YOUR WEAK RELAY
PERFORMANCE!
Just once I would like
a fair relay race.
Last year I was
almost boiled alive.
this year the water is
going the wrong way!
Why does this place
make it so hard!
AAcrazed
water manipulation
manipulation to
toattack
attackthe
theother
crazed coach
CoachH20
H20 uses
uses his
his power
power of
of water
other
He doesn’t
stop
the Edison
swimmers.
also
team.team.
He doesn’t
stop at
the at
Edison
MiddleMiddle
SchoolSchool
swimmers.
He alsoHe
goes
goes
the Edison
Tesla Middle
School
fans. No one is excluded
after after
the fans.
No one and
is excluded
from the
chaos.
from the chaos.
PHYSICSQUEST: SPECTRA - TURBULENT TIMES (ISSUE #5)
ACTIVITY 3 - A
TEACHER GUIDE
ACTIVITY 3: Vortex Cannon
INTRO
We’ve all watched The Hobbit, Bilbo Baggins blow
smoke rings or watched whirlpools in the tub. Even dolphins like to play with bubble rings. Why does the air always end up in a circle? What happens if you try to force
the air into other shapes such as a square or a triangle? In
this experiment we will build a “vortex cannon” and see
what happens when air is forced out through a rectangular or triangular hole instead of a circular one. In Activity
2 you looked at how water flowed around objects, now
you are going to look at how it flows through holes.
KEy TERMS
Vortex: Fluid that is flowing in swirls instead of a straight
line. Whirlpools are a type of vortex.
Torus: A shape like a donut or a bagel
MATERIALS
n Rubber band
n Plastic bag
n Tissue paper
n * Paper cup
n * Adhesive tape
n * Scissors
n * Index cards
*Not included in the PhysicsQuest Kit
BEFORE THE ACTIVITY, STUDENTS
SHOULD KNOW
n The definition of a vortex and a torus
AFTER THE ACTIVITY, STUDENTS
SHOULD BE ABLE TO
n Say which shape allows the air from the cannon to
travel the farthest.
n Describe why a vortex travels the farthest.
n Explain why the air pushed through a triangle and a
square do not create a vortex
THE SCIENCE BEHIND
THE VORTEX CANNON
We see vortices everywhere, from flying cows in “Twister” to watching the tub drain. One thing that is always
the same, they move in a circular pattern. You’ll never
see a square tornado or a triangular whirlpool. But why
is that? Is it just that they always start as circles so they
stay that way? What would happen if a tornado started off
in the shape of a triangle, would it stay in that shape? It
turns out the answer is “no” for the same reason you can’t
make a square bubble.
KEY QUESTION
Which vortex cannon shape will
allow air to travel the farthest?
This experiment involves building a “vortex cannon”
which is just a fancy way of saying something that pushes a puff of air through a hole to create a traveling ring
of air. You’ve probably played with that evil toy, the “airzooka” which does a great job smacking people in the
face with a huge, strong blast of air. How is it able to
move air like that? There are two components to making
a good vortex cannon, being able to push the air with lots
of force and shaping the hole through which the air exits
correctly. In the case of our homemade cannon, the air is
pushed using a rubber band and a plastic bag. The rubber
band is stretched when the bag is pulled back and air is
pulled into the cup. When you let go of the bag, the rubber band pulls it in quickly and air is rapidly pushed out
of the front of the cannon. If the mouth of the cannon is
in the shape of a circle, a vortex is created.
A vortex is any type of twist or swirl in a fluid. The neat
thing is that vortices are extremely stable, meaning its
difficult to change their motion. So if you manage to
create a vortex of air, it’s going to take a lot to get it to
change. A vortex is created by the cannon because as the
puff of air passes through the hole the outside gets a little
caught on the edge and gets slowed down. The middle
part of the puff has no such problem and ends up traveling faster. Because of the speed difference, the air in the
middle starts swirling out towards the outside as the air
from the outside starts swirling back in. What’s created is
a donut of air that is swirling from the inside out. The air
has no particularly reason to stop doing what it’s doing.
It is extremely stable and travels easily through the surrounding air without being slowed down much. It also
won’t easily break apart. This is why tornados and bathtub swirls don’t break up that easily. (Fig. 1)
What would happen if the front of the cannon had a shape
other than a circle? Because of the edges of any shape
other than a circle, the air leaving the cannon isn’t forced
into a vortex. Which means its not very stable and won’t
travel as far. Some shapes may be close enough to a circle
to create a weak vortex, but it won’t be nearly as good as
a circular opening. (Fig. 2)
Because there is no good way short of a fog machine to
see a vortex, this experiment uses tissue paper flags to see
PHYSICSQUEST: SPECTRA - TURBULENT TIMES (ISSUE #5)
ACTIVITY 3 - B
TEACHER GUIDE
ACTIVITY 3: Vortex Cannon
how far the puffs of air from different cannon shapes goes. It is important to make the circular
opening as close to a circle as possible to get the best effect.
If you would like a video explaining how to make the paper cup vortex cannon, visit this site:
http://construction-toys.wonderhowto.com/how-to/make-air-vortex-cannon-272086/
The materials are different, but the principle is the same.
SAFETY
n Review these guidelines closely with students before the activity and outline consequences
for failure to follow them! Always be careful with scissors and rubber bands. Stretched rubber bands can hurt if they are let go too quickly.Be cautious when cutting out shapes as it is
sometimes difficult to cut a shape out of the center of a card. With younger students this part
should be done by an adult.
Corresponding Extension Activities
n Air Flow
n Siphoning
n Cold Lava Lamp
Bibliography/Suggested Resources
n http://thesciencepresenter.wordpress.com/2011/01/16/wheres-the-science-airzookas/
n http://www.physicscentral.com/experiment/physicsathome/cannon.cfm
n http://amasci.com/wing/smring.html
Figure 1
Figure 2
PHYSICSQUEST: SPECTRA - TURBULENT TIMES (ISSUE #5)
ACTIVITY 3 - C
STUDENT GUIDE
ACTIVITY 3: Vortex Cannon
INTRO
We’ve all watched The Hobbit, Bilbo Baggins blow smoke
rings or watched whirlpools in the tub. Even dolphins like
to play with bubble rings. Why does the air always end
up in a circle? What happens if you try to force the air
into other shapes such as a square or a triangle? In this
experiment we will build a “vortex cannon” and see what
happens when air is forced out through a rectangular or
triangular hole instead of a circular one. In Activity 2 you
looked at how water flowed around objects, now you are
going to look at how it flows through holes.
KEy TERMS
Vortex: Fluid that is flowing in swirls instead of a straight
line. Whirlpools are a type of vortex.
Torus: A shape like a donut or a bagel
MATERIALS
n Rubber band
n Plastic bag
n Tissue paper
n * Paper cup
n * Adhesive tape
n * Scissors
n * Index cards
*Not included in the PhysicsQuest Kit
GETTING STARTED
n Think about whirlpools. What shape are they in?
n Now think about smoke rings, what shape are they in?
n Why do you think they are in those shapes and not others?
n Do you think their shape affects how they move?
SETTING UP THE EXPERIMENT
This can be a bit tricky. If you are having problems,
ask your teacher for help, he or she can show you a
video of how it’s done (Fig. 1).
Making the cannon
1. Cut the bottom out of the paper cup as cleanly as possible.
2. Cut the bag so that it is one sheet of plastic.
3. Lay the cup top down on the piece of plastic and trace
it.
4. Cut the plastic into a circle that has a radius 3-inch
bigger than the top of the cup.
5. Cut two small slits about half an inch apart in the center of the plastic circle.
KEY QUESTION
Which vortex cannon shape will
allow air to travel the farthest?
6. Cut the rubber band so it is a rubber strip instead of a
rubber band.
7. Thread the two ends of the rubber band through the
two slits and tape the plastic to the rubber band. Use
plenty of tape.
8. Again lay the cup top down over the center of the plastic, but this time thread the rubber bands up through the
bottom of the cup.
9. Pull rubber bands up and out of the bottom of the cup.
As you do this the disk of plastic will be pulled up and
into the cup. Keep pulling the rubber bands until the plastic has been pulled half of the way into the cup. Fold the
rubber bands around down to the outside of the cup and
tape. Use lots of tape.
10. Take the plastic disk and fold the outside edges up
and around the outside of the cup. Tape very tightly. Use
lots of tape and make sure it is all sealed very well.
You should now have plastic at one end and an opening at the other. When you pull the plastic back you
should be able to let it go and have air forced out of
the hole.
Making the cards and flags
1. Take three index cards and draw a circle on one,
square on another and triangle on the third
2. Carefully cut out the shapes.
3. Take the tissue paper and cut into one inch squares.
These will be used as “flags.” (Fig. 2)
4. Tape the flags to a long bookshelf or a series of
desks so that they are one inch apart. They should
have one free side just like a flag so that if air rushes
by it can flap in the wind. This is how you are going
to test to see how far your air cannon can shoot.
PHYSICSQUEST: SPECTRA - TURBULENT TIMES (ISSUE #5)
ACTIVITY 3 - D
STUDENT GUIDE
ACTIVITY 3: Vortex Cannon
EXPERIMENT
1. Put a line of tape on the floor 1 meter away
from the first flag.
2. Tape the index card with the triangle and
tape it to the front of the cannon so that when
“fired” the air will be forced through the triangular hole.
3. Stand on the tape line and “fire” the air cannon so that the puff of air hits the edge of the
flags. It may take several tries to aim correctly.
Once it is lined up, shoot the cannon at the flags
10 times and count how many flags wiggle
each time.
_____________________________________
_____________________________________
_____________________________________
4. Average these numbers together to get the
average number of flags that wiggled.
5. Repeat these steps with the square and circle.
5. How far do you think air would travel if
forced through a hexagon? How about an octagon?
_____________________________________
_____________________________________
_____________________________________
6. Using your results to help Spectra and the
gang find the kitchen.
_____________________________________
_____________________________________
_____________________________________
Which shape allowed the air to go the farthest?
1.Triangle (The gang should go straight)
2. Square (The gang should go left)
3. Circle (The gang should go right)
RECORD THE AVERAGE HERE
Triangle ______________________________
Square _______________________________
Figure 1
Circle ________________________________
ANALYZING YOUR RESULTS
1. Which shape allowed the air to travel the
farthest?
_____________________________________
_____________________________________
Rubber
band
Tape
Plastic
2. What is one big difference between the circle
and the other two shapes?
_____________________________________
_____________________________________
3. Rank the shapes in order from most corners
to least corners. How does this compare to the
ranking of distance traveled?
_____________________________________
_____________________________________
_____________________________________
4. What shape are smoke rings and how does
the shape that allowed the air to travel the farthest compare?
_____________________________________
_____________________________________
_____________________________________
Slits
Tissue paper
Figure 2
I have an idea!
c’Mon
Let’s HEAD
TO THE
CAFETERIA.
We’ve got to stop
COACH! I’M NOT FAN OF
Edison Middle School
EITHER, but he’s REALLY
hurtING PEOPLE!
He’s too powerful
and I don’t know what
my laser powers can
DO AGAINST HIM!
OK! BUT I THINK IT’s
TIME FOR SPECTRA TO
MAKE AN APPERANCE!
The quartet of young
heroes burst into the
school’s kitchen.
Over there,
get the ketchup,
it’s thick!
BUT GUYS, Isn’t
there water
in ketchup?
YOU’RE RIGHT RUBY,
REMEMBER WHAT WE
learnED IN PHYSICS CLASS.
We’RE just going
to make it
easier for him,
not trap him.
when you move ketchup,
it BECOMES easier to move.
Lucy, help ME with this
corn starch!
How is a laser
suPPosed to help
you move stuFF?
A LASER CAN’T,
but you CAN! aren’t
you a swimmer with
big arms? Forget
the laser stuFF
and HELP! BTW, why
are you in YOUR
spectra outfit?
I Just felt like
I should be READY.
we are saving the
school, aren’t we?
Thegroup
group takes
takes all the
and
The
the ketchup
corn starch
corncan
starch
they
they
carry
to can
the carry
pool. to the pool.
Hey Coach, over here!
If you want to attack
someone, attack me!
I’m the one that lost
the big relay.
It’s my fault.
we lost!
While
the Coach
coachis
isdistracted
distracted
While the
by
Spectra,
Gordy,
Rubyand
and
by Spectra, Gordy, Ruby
Kas
take
the
tops
off
the
corn
Kas take the tops off the corn
starch.
starch and ketchup.
Lucy?!!
The Coach
coach focuses
focuseshis
his
attention on
attention
onSpectra
Spectraand
andhehe
loses control
controlof
ofthe
thepool’s
pool’s
water. He
water.
He stumbles
stumblesand
andfalls
falls
back into
back
into the
thepool.
pool.
Spectra yells,
Spectra
yells,“Gordy,
“Guys, your
the plan
plan is working.”
is working.”
DUMP IT
NOW!
Everyonedumps
dumpsthe
thecorn
corn
Everyone
starch
in the
starch and
intoketchup
the water.
water.
They make
a mess!
They make
a mess!
FooLISH
CHILDREN,
you can’t
trap me!
HE HA!
DE HA!
HA DA!
Coach
attempts
at the
theaquatic
aquaticcenter.
center.
Coach
attemptstotocontinue
continuehis
his outburst
outburst at
HeHe
tries
totocreate
inmixing
mixingthe
the
tries
createaavortex
vortexand
and only
only succeeds
succeeds in
corn
starch
and
water and
evenwater
more.
Themore.
moreThe
he more
tries to
corn
starch,
ketchup
even
he move
tries
thetowater,
thickerthe
the
mixture
move the water,
thicker
thebecomes.
mixture becomes.
PHYSICSQUEST: SPECTRA - TURBULENT TIMES (ISSUE #5)
ACTIVITY 4 - A
TEACHER GUIDE
ACTIVITY 4: Do You Want Ketchup with Your Physics?
INTRO
“Viscosity” is a term that describes how easy it is for
a fluid to flow. For most types of fluids, the viscosity
doesn’t change. These fluids are called “Newtonian”
fluids. But there are certain types of fluids that change
viscosity if they are moving. In this experiment you
will play with two “Non-Newtonian” fluids and learn
why tapping a ketchup bottle will make your fries tastier more quickly.
KEy TERMS
Viscosity: A measure of how easily a fluid flows. The
higher the viscosity, the more difficult it is for the fluid
to flow.
Newtonian Fluid: A fluid that has the same viscosity
no matter how fast it is flowing. Most fluids you have
ever seen are “Newtonian Fluids.”
KEY QUESTION
How does the flow of ketchup and
oobleck change when they are stirred?
AFTER THE ACTIVITY, STUDENTS
SHOULD BE ABLE TO
n Define “viscosity”
n Explain that ketchup and oobleck flow differently
when they are stirred.
n Be able to determine if a fluid is “shear-thinning” or
“shear-thickening”
Non-Newtonian Fluid: A fluid whose viscosity depends on how fast it is flowing.
n Explain why “tapping the 57” works to get ketchup
out of a bottle.
Shear-Thinning Fluid: A fluid whose viscosity decreases the faster it flows. Stirring or shaking will decrease the viscosity
THE SCIENCE BEHIND
DO YOU WANT KETCHUP WITH YOUR PHYSICS
Shear-Thickening Fluid: A fluid whose viscosity
increases the faster it flows. Stirring or shaking will
increase the viscosity
MATERIALS
n Tart pastry pans (4)
n “Sand” made of small green beads
n Ketchup
n * Water
n * Adhesive tape
n * Scissors
* Not included in the PhysicsQuest Kit
NOTE: It’s possible to let the oobleck made with the
glass beads dry out so that the beads can be reused.
BEFORE THE ACTIVITY, STUDENTS
SHOULD KNOW
There are tons of different types of fluids, from coffee (yum!) to things like molasses. A fluid is anything
that flows. I’m now required by high school physics
teachers around the country to point out that gases are
also fluids. They also can flow. We’re used to fluids
such as water that flow in the same way no matter how
fast they are moving. Since stirring those can be about
as interesting as watching paint dry, this experiment is
going to show fluids that don’t do what you’d expect.
When talking about fluids one of the most important
properties to look at their its viscosity. The best conceptual way to think of viscosity is that it is a measure
of how much a fluid resists flowing. Water has a lower
viscosity than honey. There are special types of fluids
called “superfluids” that have zero viscosity at very
low temperatures, as low as -459 degrees Fahrenheit.
They can move almost forever without stopping.
n Most fluids flow in the same way no matter if they
are flowing fast or slow.
On the opposite end of the scale are fluids that have
such high viscosity that they actually look like solids.
n Oobleck is a material usually made of cornstarch
and water. It can also be made of glass spheres as it is
in this experiment.
One famous example is pitch. There is an experiment
that watches pitch drip from a funnel and in 80 years it
has only dripped eight times. It is about to drip for the
ninth time and if you are interested in watching, a live
webcam feed can be seen here: http://smp.uq.edu.au/
content/pitch-drop-experiment In the 80 years of the
experiment, no one has ever seen it drip nor caught
the drip on camera. Here’s hoping the ninth time’s the
charm.
n Some fluids flow more easily than others.
PHYSICSQUEST: SPECTRA - TURBULENT TIMES (ISSUE #5)
ACTIVITY 4 - B
TEACHER GUIDE
ACTIVITY 4: Do You Want Ketchup with Your Physics?
For almost all fluids the viscosity doesn’t depend on
how fast a fluid is flowing. Water for example has
the same viscosity if it is moving slowly or quickly. Think of stirring hot milk on a stove, if you stir
faster it doesn’t feel any different than if you stirred
slowly. These types of fluids are called “Newtonian”
fluids. They are by far the most common and behave
as one thinks a fluid should behave. However, the
ones we are going to play with in this experiment
are called “Non-Newtonian” fluids. This means that
if they are pushed or stirred, their viscosity changes.
Sometimes they have a lower viscosity when they
are stirred and sometimes the viscosity become
greater. Stirring can also be called applying a shear
force. So, if something stiffens when stirred its
called “shear thickening” and if it gets less viscous it
is called “shear thinning.”
over one another and it can move easily. Like forming an orderly line to exit a door. (Fig. 1)
The most common Non-Newtonian fluid is corn
starch and water, called oobleck. It is often thought
that the interesting properties of oobleck are caused
because of a chemical interaction between the corn
starch molecules and the water. This is not the case.
It is shear thickening because of the shape of the
corn starch molecules. The molecules are surprisingly spherical. I’m guessing that there are many
people out there who won’t believe this right off the
bat. The PhysicsQuest kit has tiny glass beads that
are used to make the oobleck instead of the traditional corn starch as a way to convince the doubters that it is in fact the shape and not the chemicals.
But why do these spheres cause the oobleck to “lock
up” when it’s stirred quickly? When you try to move
a spoon or your finger through oobleck, the tiny
spheres have a hard time moving around each other
and the water molecules quickly enough to flow. It’s
as if they jam up against each other like people all
trying to squeeze through a door in a mad rush to get
Justin Bieber’s autograph. But if it is pushed more
slowly there is time for the particles to roll and slide
Scientists are actively doing research on these interesting fluids to find out more about why and how
they move as they do. In a lot of types of manufacturing it is critical to know how fluids move to make
sure production works smoothly. So have a great
time playing and experimenting with some messy,
tasty physics.
Ketchup is not often thought of as Non-Newtonian,
it is usually just thought of as hard to get out of the
bottle. I wish I could give an simple explanation of
why ketchup is a shear-thinning fluid, but I can’t.
In fact, people are still actively researching how
the ketchup molecules move and why that makes
ketchup behave like it does. I think it’s pretty neat
that scientists are actually studying the movement of
ketchup! Ketchup is really made of ground up tomato suspended in a sugar-water solution. The current
most plausible explanation is that when the ketchup is sitting still the tomato molecules are moving
around randomly but when it is pushed they line up
and slide over each other more easily. (Fig. 2)
SAFETY
n Review these guidelines closely with students before the activity and outline consequences for failure
to follow them! Do not inhale the glass beads. If a
large quantity is directly inhaled it can cause lung
problems. Be careful to monitor students when using the ketchup packets. If stepped on on rolled over
they can cause quite a mess.
Corresponding Extension
Activities
n Moon Blob Gel
n Comparing the Viscosity of Fluids
n Anti-Bubbles
Bibliography/Suggested Resources
n http://physicsbuzz.physicscentral.com/2012/04/non-newtonian-barry-white.html
n http://physicsbuzz.physicscentral.com/2012/05/nanotech-and-condiments.html
n http://www.instructables.com/id/Oobleck/
n http://arstechnica.com/science/2005/11/1771/
Figure 1
Stirring slowly
Stirring quickly
Ketchup
Figure 2
PHYSICSQUEST: SPECTRA - TURBULENT TIMES (ISSUE #5)
ACTIVITY 4 - C
STUDENT GUIDE
ACTIVITY 4: Do You Want Ketchup with Your Physics?
INTRO
You’ve probably been in the situation where you’ve
tried to dump ketchup on your fries but it just won’t
come out of the bottle. You’ve also probably had someone tell you to “tap the 57” to get the ketchup to flow
and its worked. This isn’t some magic little trick, it’s
physics and you are going to learn why. If you’ve ever
played with “oobleck,” the fun mixture of corn starch
and water, you know it does the opposite. When you
move it slowly, it flows but if you try and move it fast,
it becomes impossible. You’re going to get to learn all
about this in this experiment.
KEy TERMS
Viscosity: A measure of how easily a fluid flows. The
higher the viscosity, the more difficult it is for the fluid
to flow.
Newtonian Fluid: A fluid that has the same viscosity no
matter how fast it is flowing. Most fluids you have ever
seen are “Newtonian Fluids.”
Non-Newtonian Fluid: A fluid whose viscosity depends on how fast it is flowing.
Shear-Thinning Fluid: A fluid whose viscosity decreases the faster it flows. Stirring or shaking will decrease the viscosity
Shear-Thickening Fluid: A fluid whose viscosity increases the faster it flows. Stirring or shaking will increase the viscosity
MATERIALS
n Tart pastry pans (4)
n “Sand” made of small green beads
n Plastic spoon
n Ketchup
n * Water
n * Adhesive tape
n * Scissors
* Not included in the PhysicsQuest Kit
NOTE: It’s possible to let the oobleck made with the
glass beads dry out so that the beads can be reused.
GETTING STARTED
1. When you hold a bottle of ketchup upside down
(not the squeezy kind), what happens? Does it flow?
2. What would happen if you did the same with a
bottle of water?
3. What do you think is the difference?
KEY QUESTION
How does the flow of ketchup and
oobleck change when they are stirred?
4. If you’ve played with oobleck (a mixture of corn
starch and water), what happens when you pour it
slowly? What happens when you smack it?
5. If your parents/teachers will let you use the Internet, ask them to show you the video of people running across pools of corn starch and water mixtures.
6. The “sand’ you are using to make oobleck is made
of tiny glass spheres, not corn starch. Do you think
oobleck moves the way it does because of the fact
corn starch is also tiny spheres or because there is
some chemical interaction between the cornstarch
and water?
SETTING Up THE EXPERIMENT
n You will be making two of the tart pans into funnels
1. Take two of the tart pans and cut a slit from the
outside to the center of the pan.
2. Roll the pans into a cone shape.
3. Cut of the tip of the cone off to make a funnel
n Making the ketchup solution
1. Squeeze the contents of the two ketchup packets
into a cup.
2. Add 2 spoonfuls of water to make the ketchup
slightly less viscous.
3. Stir until the solution is well mixed.
n Making the oobleck
1. Place 5 spoonfuls of glass “sand” in a cup.
2. Add 3-4 spoonfuls of water and mix.
3. The mixture should become hard to stir if the
spoon is pushed through quickly, but if you move it
slowly it should still be moveable. Add more “sand”
or water as needed to get the right consistency.
PHYSICSQUEST: SPECTRA - TURBULENT TIMES (ISSUE #5)
ACTIVITY 4 - D
STUDENT GUIDE
ACTIVITY 4: Do You Want Ketchup with Your Physics?
TIME TO GET MESSY!
ANALYZING YOUR RESULTS
n Drip Test
If ketchup and oobleck were allowed to drip
through a funnel, how do you think the dripping
will change when they are stirred? Will it be the
same for the ketchup and the oobleck?
1. Hold one of the funnels over a tart pan.
2. Fill the funnel with ketchup. Record what happens. __________________________________
______________________________________
______________________________________
3. Take the spoon and stir the ketchup in a circle,
don’t try and push it through the hole in the funnel. Record what happens. _______________
_______________________________________
_______________________________________
4. Stop stirring. Record what happens.
_______________________________________
_______________________________________
_______________________________________
5. Start stirring again. Record what happens.
_______________________________________
_______________________________________
_______________________________________
1. When the ketchup was poured into the funnel,
what happened? What about the oobleck?
_______________________________________
_______________________________________
2. What happened to the ketchup when you
stirred it? What about the oobleck?
_______________________________________
_______________________________________
_______________________________________
3. Viscosity is a measure of how easily a fluid
flows. Does the viscosity of the ketchup change
as you stirred it? Did it increase or decrease?
What about the oobleck?
4. When a fluid is “shear-thinning” it means it
flows more easily when it’s shaken or stirred.
A “shear-thickening” fluid does the opposite.
Is ketchup shear-thickening or shear-thinning?
What about oobleck?
_______________________________________
_______________________________________
_______________________________________
6. Repeat these steps with the oobleck.
_______________________________________
_______________________________________
_______________________________________
USING YOUR RESULTS TO HELP SPECTRA FIND THE KITCHEN
How does the viscosity of the ketchup and the oobleck change when they are stirred?
1. Both ketchup and oobleck are shear-thinning. (The gang should go straight.)
2. Ketchup is shear-thinning and oobleck is shear-thickening. (The gang should turn left.)
3. Both ketchup and oobleck are shear-thickening. (The gang should turn right.)
Images not to scale
Tart pan
Cut to center
Twist into
a funnel
Cut off
the tip
Apparently,
this one does.
HA HA hA!
Sorry!
American Physical Society
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All Rights Reserved