HAZLETON AREA SCHOOL DISTRICT
DISTRICT UNIT/LESSON PLAN
Teacher Name :
Building : WHEMS
Rebecca Rutkowski
Subject :
Work and Simple Machines
Start Date(s):
April, 2015
Grade Level (s): 7
DAILY PLAN
Unit Plan
Unit Title: Work and Simple Machines
Essential Questions:
1. How do scientists define work?
2. What is the importance and usefulness of the many machines around us?
3. How do you calculate the ideal vs. actual mechanical advantage of each simple machine?
4. How does the mechanical advantage of machines make work easier?
Standards: PA Core Standards, PA Academic Standards/Anchors (based on subject)
3.2.8.B1 Explain how inertia is a measure of an object’s mass.
Explain how momentum is related to the forces acting on an object.
3.2.8.B2 Identify situations where kinetic energy is transformed into potential energy, and vice versa.
3.2.8.B3 Explain how changes in temperature are accompanied by changes in kinetic energy.
Assessment Anchors:
• S8.C.3 Principles of Motion and Force
• S8.C.3.1.3 - Explain that mechanical advantage helps to do work (physics) by either changing a force or changing the direction of the applied force (e.g., simple
machines, hydraulic systems).
Summative Unit Assessment :
Summative Assessment Objective
Students will-understand and calculate mechanical advantage using simple machines
Overview of Unit:
Through a five-lesson series with five activities, students are introduced to six simple
machines—inclined plane, wedge, screw, lever, pulley, wheel-and-axle—as well as
compound machines, which are combinations of two or more simple machines. Once
students understand about work (work = force x distance), they become familiar with
the machines' mechanical advantages, and see how they make work easier.
Assessment Method (check one)
____ Rubric ___ Checklist ____ Unit Test ____ Group
____ Student Self-Assessment
___x_ Other (explain) Students utilize interactive notebooks, which
incorporate all of the above
Objective (s)
Students will identify when
work is done on an object.
DOK
LEVEL
1,2
Grouping
Day
Activities / Teaching Strategies
Foldable-“Calculation of Work”
i
Materials / Resources
Handouts
Text
Assessment of Objective (s)
Formative-calculations.
Vocab: work, joule, power
1
Calculate work done on a
project
SummativeStudent Self - Assessment-
Define and calculate power
Students will be able to
explain how machines make
work easier.
1,2
Vocab: machine ,input force, output force,
Input work, output work, mechanical advantage, efficiency.
Paper, pencils, notes
i
Formative-chapter page 411,
Questions 1,2,3,4
Summative-
Calculate the mechanical
advantage of a machine
Calculate the efficiency of a
machine
It is well known that simple machines can make work
easier, but exactly how much easier? The answer to this
question is known as mechanical advantage, which is
defined to characterize a machine's ability to lessen the
burden of work.
Student Self - Assessment-
Mechanical advantage is the number of times a force
exerted on a machine is multiplied by the machine, in other
words, the degree to which a machine makes work easier.
Recall from Lesson 1 that the mechanical advantage of all
machines is defined by the general expression:
2
However, this expression is too general and so it is
necessary to define specifically the mechanical advantage
of each machine in terms of its own unique mechanics.
Furthermore, only the ideal, or theoretical, mechanical
advantage of each simple machine is presented in this
lesson since the actual mechanical advantage cannot be
determined in advance.
3
Calculate the efficiency 1,2
of a machine
(Same as day 2)
Paper, pencils,notes
Same as Day 2 (above)
i
Formative-calculating
efficiency problems p 418
1,2
p.419 4,5
Students will be able to
explain how machines make
work easier.
2,3,4
Calculate the mechanical
advantage of a machine
Calculate the efficiency of a
machine
4
Introduce vocabulary: Machine: A device that allows you
to do work by transmitting or modifying force or motion.
Mechanical Advantage: The ratio of the output force
produced by a machine to the applied input force or the
factor by which a mechanism multiplies the force applied
to it.
Work: Force times distance moved. W = F x D.
Inclined Plane: A simple machine involving a flat surface
with one end higher than the other.
Lever: A simple machine consisting of a bar that rotates on
a fixed point (its fulcrum, or pivot point) so that force
applied to one point on the bar will exert force against a
load on another point on the bar.
Wheel-and-Axle: A simple machine consisting of a
modified lever that rotates in a circle around a center point
or fulcrum.
Pulley: A simple machine utilizing a wheel or set of
wheels with grooved edges over which a rope or chain can
be drawn in order to change the direction of a pulling force
and increase the capacity for lifting weight
G,i
stations
Formative-drawings of
simple machines
Summative- Drawing Race:
Write the six simple
machines on the board
(screw, lever, wheel-andaxel, pulley, wedge and
inclined plane. Divide the
class into teams of four,
having each team member
number off so each has a
different number, one
through four. Call a number
and a simple machine. Have
students with that number
race to the board to draw the
simple machine. Give a point
to the team whose teammate
first finishes the drawing
correctly
Student Self - AssessmentRecognize and identify the
six simple machines.
Define the concept of work.
5
Explain why engineers are
interested in simple
machines.
2,3,4
1.Arrange students into groups of 3.
2. Distribute copies of the Simple Solution Instructions.
Give the groups 5 minutes to brainstorm ideas and discuss which
idea they think is their most promising.
Note: There is no material constraint except for a limited budget;
however, it is important that the device is made out of appropriate
materials for the task. For example, the material that wraps
around the elephant to pick it up should not be tissue paper since
it is not nearly strong enough nor should it be made of titanium,
since that is too expensive.
Give students 10 minutes to make a drawing on white paper
that illustrates the device and explains how it will work.
Note: This can be highly creative. Try to help students think
through the problem using simple machines. For example, try to
avoid electronics. Instead of a button you push to raise the
device's arm, there might be a hand crank (wheel-and-axle).
Have each group present their invention for one minute,
describing how it works and how it is put together.
After each group has presented, ask the class to identify some
common solutions to the problem. Which were the most
expensive designs? Were the less expensive designs feasible?
How did the designs demonstrate the safety for the elephant?
g
Pencil, with eraser
Ruler
Colored pencil or marker
(optional)
1-2 piece of white paper (can
be used on one side)
Copy of the Simple Solution
Instructions
Formative-“Simple
Solution” activity
Summativ
Student Self - Assessment-
Why is the elephant's safety important to the circus?
6
Students willExplain how the inclined
plane, wedge and screw
make work easier.
Identify how the inclined
plane, wedge and screw are
used in many familiar
engineering systems today.
Discuss the mechanical
advantage of an inclined
plane, wedge and screw.
2,3,4
Calculate the mechanical
advantage of a pulley.
Explain why the concept of
mechanical advantage is
useful for engineers.
Perform engineering design
work in a group
2,3,4
This lesson introduces students to three of the six
simple machines used by many engineers. These
machines include the inclined plane, the wedge and
the screw. In general, engineers use the inclined plane
to lift heavy loads, the wedge to cut materials apart,
and the screw to convert rotational motion into linear
movement. Furthermore, the mechanical advantage
describes how easily each machine can do work and
is determined by its physical dimensions.
1.
2.
3.
4.
5.
7
Distribute materials and the Pulley Worksheet.
Allow students to stand on desks or ladders to hang the
two-wheeled pulley on the ceiling,
Have the students follow the instructions on the Pulley
Worksheet for measuring the weight (load) of the
object, effort and mechanical advantage of several
pulley systems.
Have the students discuss the theoretical mechanical
advantages in comparison to the actual ones.
Lastly, engage the students in discussion of their
activity. What were some possible sources of error in
their procedure? What recommendations would they
make as engineers to the aquarium trying to move the
gray whale back to the ocean? Would they use
pulleys? What are some constraints that they as
engineers might consider while designing a pulley
system for the whale? What impacts to the whale
might they need to consider for moving it back to the
ocean
G,i
Materials List
Formative- Lab sheet
“Inclined Plane” WS
For whole class:
8 clamps and stands
8 plywood sheets about 10cm
(4 in) wide and 2 each of the
following lengths: 30cm,
60cm, 90 cm, and 120cm.
G,i
Each group needs:
Spring scale
Meter stick
Small car (i.e., rolling toy)
with a string attached
Weight (same size for each
group)
4 copies of the Inclined Plane
Worksheet
Each group needs:
 Approximately 20 feet
of nylon rope
 Two-wheeled pulley
 Single pulley
 Spring scale
 String
 Weight (can use soup
cans, rocks, weights,
etc.)
 3 copies of the Pulley
Worksheet
Formative: the Pulley
Worksheet
Then: Post-Activity
Assessment
Design Requirements and
Constraints: Have the
students make a list on the
board of the problem's
design requirements and
constraints. Some examples
might include: budget for
materials, time, safety and
impact on the whale, ethical
and social impacts.
Engineering Design:
Engineers need to be able to
communicate their ideas
effectively to their audience.
Have students create a
design of their pulley system
on a blank sheet of paper for
the aquarium. What
recommendations would
they make as engineers to
the aquarium trying to move
the gray whale back to the
ocean? What is some other
information they might want
to know in order to design
their lift effectively?
Journal Writing: Have
students write a journal entry
on the results of the activity.
The entry should summarize
the results and discuss why
knowing the mechanical
advantage of a machine is
useful. information they
might want to know in order
to design their lift
effectively?
students will:
Recognize how compound
machines are used in many
familiar engineering
systems today and name
several found in daily life.
Explain the difference
between compound and
simple machines.
Explain how to calculate the
mechanical advantage of
compound machines.
8.
2,3,4
Who can tell me why a door is considered a compound
machine? (Answer: It consists of two simple machines
working together: the hinges and the door knob.)
When we come across a machine that is not
functioning, it becomes apparent how much we depend
on it. How would you open a can with no can-opener,
or a latched door without a knob? We use these
mechanical things every day. Who has another
example of a compound machine you would miss?
(Possible answers include: your bike or your
adjustable basketball hoop or the pencil sharpener.)
One way to talk about the value of a compound
machine is by referring to its mechanical advantage.
What is \ mechanical advantage? (Answer: Mechanical
advantage is a way engineers quantitatively, or with
numbers, talk about the effectiveness of a machine, or
how much easier it makes work.)
There is a specific reason why we miss machines when
they aren't functioning. Is it because you are friends
with the machine you are saddened when it is not
completely healthy? Probably not. It saddens you
because it no longer works for you. Can you think of a
day when you did not use a simple or compound
machine? These devices which make work easier for
us tend to be a valuable part of our day-to-day life.
w,I,G
Use the engineering design
process to create a compound
machine – the catapult.
Describe the interrelationship
of the simple machines
within a compound machine.
Describe the constraints of
their model in the context of
engineering.
Lesson Summary
Assessment
Drawing: Have the students
draw a picture of an existing
or made-up compound
machine, one that is made of
two or three simple
machines. Remind them to
include where the force is
applied and the machine's
end function.