Association of Future Science Educators
Science Demonstrations & Activity Night
May 10, 2004
Up in smoke!
Observations & Inferences - Candle observation
Boil water in a paper bag
Burning Money
Egg-siting Egg-speriments!
Egg in a Bottle
Diving eggs
Egg into a Sheet
Diffusion & Osmosis- Bouncing Eggs
Bonus osmosis demo!
Camouflage Eggs
Egg Cars
Polymers
Slime & Slimy Substances
Super balls & Silly Putty
Skewered Balloons
Balloon Stretch
Happy & Sad Balls
Super Absorbent Polymers
Electric Pickle
Magic Oven
Conservation of Volume – Not!
Icy Experiments
Sinking & Floatin
.
Lift an ice cube with salt!
Air Pressure & Bernoulli’s Principle
Blow a ping-pong ball out of a funnel.
The Bernoulli Pop Can Ghost
Why does that happen?
Air pressure does that, too?
Are you thirsty?
Bubbles Aloft!
The Coke Can Crusher
The Balloon in the Flask
AFSE Science Demonstration & Activity Night
5/10/04
AFSE Science Demonstrations & Activity Night 5/10/04
Directions & Resources
Up In Smoke
Candle observation – the Edible Candle
Use an apple corer to get a cylindrical piece of apple or potato.
Place a sliver of almond into the top as a wick.
Place your potato candle into a candle holder & light the “wick”.
Have students make observations of the candle.
After giving time to write their observations take a bite of the candle.
Discuss the differences between observations and inferences.
http://www.tc.unl.edu/nerds/mamres/demos/physical/now_you_see_it.htm
Boiling Water in a Paper Cup or Paper Bag
Materials:
Bunsen Burner
Paper Cups (bottom can't have edges pointing down)
Saucepan
Water
Forceps
Thermometer
Procedures
Hold a paper cup with the forceps over the flame of the bunsen burner. Show how readily the cup will burn. Do
this near a sink or a pan of water so that you can extinguish the fire.
Fill the cup with water. Measure the temperature of the water. Using the forceps, hold the cup of water over the
flame. You can do this until the water begins to boil. You can then recheck the temperature. Point out to the
students that the tip of the flame is hotter than 3000 F or 1650 C. If you fill the cup only half full, you can place
it for enough into the flame so that the top 1/2 of the cup will start to burn while the bottom ½ with the water in it
remains intact.
Source: Kardos, Thomas, 75 Easy Chemistry Demonstrations,J. Weston Walch Publisher, Portland, Me, 1996.
Burning Money
Mix a water and alcohol solution (approximately 70% alcohol). Using tongs, dip a piece of paper into the
solution and light it on fire. Flames will appear but the paper will not burn. Once you have perfected the ratio of
water and alcohol do it with money. Not only will the money be "safe" from burning, it will get cleaned!
For safety purposes, have a large container of water nearby in case a fire does start.
Egg-siting Egg-speriments!
Egg in a Bottle
MATERIALS:
1. 1 hard boiled egg (w/o shell)
2. bottle or flask
3. Accordion folded 4x4in piece of paper
4. matches
PROCEDURE:
1. Light the piece of paper on fire.
2. Quickly drop the paper into the bottle and immediately place the egg over the opening.
3. The egg should drop into the bottle. Now to get it out, rinse the bottle out with water.
4. Turn the bottle upside down so the egg drops into the mouth of the bottle. Blow as hard as you can into
the bottle. When you stop blowing, the egg will drop out!
QUESTIONS:
1. Why does the egg drop into the bottle?
2. What happens to gases as they are heated?
3. What is a vacuum?
4. What element is required by fire?
AFSE Science Demonstration & Activity Night
5/10/04
RATIONALE As the paper in the bottle burns, the gases inside the bottle are heated and expand. (These
gases are both air and the gases produced by the burning of the paper). The pressure inside the bottle
increases causing some of the gases to be forced out past the egg. This acts as a one-way valve. When the
flame burns out, the gases cool and contract which in turn causes an area of lower pressure inside the flask.
The higher air pressure outside the flask pushes the egg into the bottle.
Diving Eggs
Put a pie plate on top of a beaker half filled with water. Above the
beaker place an empty toilet paper or paper towel roll. Place the egg on
top of the tube (be sure the egg is horizontally, not vertically, aligned).
This should be directly over the beaker of water. Try to get the egg into
the beaker of water without touching the egg or the cardboard tube.
Hints? Think about how you might get a coin into a cup if the coin is on
an index card on top of the cup. In much the same way, you will want to
quickly move away the pie plate so that the egg falls into the beaker of
water below. You might want to bring a broom for clean up .
WATER
Egg into a Sheet
Nothing excites students more than the chance for the teacher to end up with egg on his face. In this session
you see two great demonstrations which use raw eggs. No mess on you, guaranteed! Egg into a Sheet is an
example of conservation of momentum and impulse.
Have 4 people hold the corners of a bed sheet. The sheet should be vertical and there ought to be a small
pocket or “gutter” at the bottom of the sheet to catch the egg. Be sure that the sheet is away from walls, desks,
tables and other hard surfaces.
Have a volunteer through a raw egg at the sheet as hard as possible (aim matters! If you miss the sheet the
egg will break!).
The egg doesn’t break! Why? The change in velocity is great (fast moving egg to stopped egg) but the amount
of time given to the egg for that change in velocity is high. This means the acceleration on the egg is lower so
the force needed to stop the egg is lower. This is the same principle as air bags and bullet proof vests.
Diffusion & Osmosis – Bouncing Eggs
Soaking an egg in vinegar dissolves the shell. What you are left with is a large, single cell with
a nice cell membrane. Water can pass in and out of this membrane.
Put the egg in Karo Syrup (or molasses) to pull the water out of the egg. Put the egg back in
water and the egg will swell up as water passes inside the membrane. Colored water in and out lets
you see just how much water has passed through the membranes.
Eggs that are full of water “bounce” – See how high the egg can be dropped from before it
breaks!
Soaking Spuds (another osmosis demo)
Materials:
A small potato sliced into several flat pieces ,Two small bowls, Table Salt
Procedure
1.
Place some pieces of the potato in one bowl and the rest in the other.
2.
Fill both bowls with water. Add two tablespoons of salt to one and label it "salt water".
3.
Let the potatoes soak for 15 minutes and compare.
Questions:
1.
Is there a difference in the firmness of the potatoes? Why?
2.
Is there a change in the amount of water in the potatoes?
3.
Where did the water go? Why?
4.
What is osmosis?
AFSE Science Demonstration & Activity Night
5/10/04
Rationale: Through osmosis, water moves from areas of low salt concentration to areas of high salt concentrations.
Adding salt to the water creates a higher salt concentration in the dish than in the potato. Consequently, water in a potato
that is soaking in salt water migrates out, leaving behind a limp spud.
Camouflage Eggs
Select an environment (classroom, outdoors – preferably one with many different habitat choices) where
students will be hiding their egg animals. Give each student a plastic egg or a hollow egg. Using various
materials the students will decorate their egg to hide in the selected habitat. Students can hide their completed
eggs during recess and the teacher (predator) will later hunt for the eggs.
Science Connections: predator/prey relations, camouflage
Egg Cars
Students will build a car. The passenger will be an egg. Completed cars will be “driven” down a ramp into a
wall. Egg passengers will ride with a seatbelt (rubber band), air bag (balloon), both or neither. Comparison of
results shows that eggs have a higher survival rate when wearing a seatbelt and using an air bag.
Polymers
Slime & Slimy Substances
There are several types of slime which you can make. You can have students make the slimes trying different
ratios of materials to see what effect that has on the slime’s properties.
GUAR GUM SLIME
 100 ml water (2-3 drops food coloring – optional)
 1/8 t guar gum
 1 t borax solution
Dissolve guar gum in water – stir until thickens (1-2 minutes)
Add borax solution and stir. The mixture should gel in 1-2 minutes.
POLYVINYL ALCOHOL SLIME
 50 ml of polyvinyl alcohol
 1 t borax solution
 food coloring (optional)
If you want to make colored slime be sure to add the food coloring to the PVA, not the borax.
Mix ingredients together in a small cup, stirring with a coffee stirrer or popsicle stick. Scrape slime out of the
cup and knead it gently with your hands until it no longer leaves a residue on your fingers.
Super balls & Silly Putty
25 ml Elmer’s Glue
25 ml of water
5 grams borax
food coloring
Mix all ingredients together. Rinse under water and pat dry between paper towels. Form into a ball and
bounce!
Use different ratios of ingredients to see what effect it has on how the ball bounces.
Skewered Balloons & Plastic Bags
Inflate a balloon and tie it shut. Insert a skewer into the balloon. Since it can slide between the cross linked
polymer chains you can do so without popping the balloon!
(helpful hints: put some oil on the skewer. Gently twist the skewer through the balloon in an area that is not
stretched very thin – near the nipple and near the tie. You will actually be able to have the skewer go all the
way through the balloon!)
Balloon Stretch
AFSE Science Demonstration & Activity Night
5/10/04
Hold an uniflated balloon next to your upper lip. Note how it feels.
Stretch the balloon and place it next to your lip. What do you feel?
After holding the balloon stretches for a while, contract the balloon and place it next to your lip. What do you
feel?
Happy & Sad Balls
Bounce these balls to see how they compare!
Superabsorbent Polymers
Sodium polyacrylate is a polymer which absorbs ~800 times its own weight in distilled water. This is the
material found in diapers and grow creatures.
Grow creature: get initial measurements of your grow creature (mass, length, width, height)
Put creature in water. Notes the creature’s changes over time.
After 1 hour:
After 2 hours:
After 4 hours:
After 8 hours:
After 24 hours:
Remove the creature from the water and make observations over time.
This can be a neat graphing exercise.
Electric Pickle
SAFETY CONCERNS: I would not do this in an elementary classroom. I never show students
how to build it and I always stress the safety aspects of the demonstration.
Zapping a pickle with electricity causes the ionization of the sodium chloride (salt). This results in an orange
glow. You can use diffraction grating or spectral line viewers to see the tell-tale sodium lines!
Magic Oven
The magic oven is a cute way to show students the difference between compounds and mixtures. Using the
magic words which make sentences “compound sentences” we mix candies together to get mixtures &
solutions.
Magic Oven Words: and, but, also, however, neither, nor, either, or, & although
Candies to use:
Orange, yellow and white candy to make candy corn
Red & white candies to make peppermint twists
Conservation of Volume – Not!
Kids often think that volume is conserved since mass and energy are. When you mix 50 grams of water and 50
grams of salt you get 100 grams of material. 50 ml of water and 50 ml of salt however, does not yield 100 ml of
solution.
Mixing liquids and getting more: Mix .5 liters of 1 M HCl with .5 liters of 1 M NaOH and you will get more
than a liter of solution. Why? NaOH and HCl combine to create NaCl and HOH (or water!). This extra mole of
water means we’ll end up with more solution than we started with.
AFSE Science Demonstration & Activity Night
5/10/04
Mixing liquids and getting less: Alcohol and water can be mixed with the resulting volume being smaller
than the sum of the parts. Why? The molecules of water and alcohol slip past each other in much the same
way popcorn and marbles can slide past each other and fill the empty spots.
These work best if you do them in a tall, narrow container or a volumetric flask.
Icy Experiments
Sinking & Floating? Does ice sink or float?
Pour water into a beaker. Pour the same amount of alcohol into an identical beaker. Place an ice cube into
each and observe.
Lift an ice cube with salt!
Challenge students to get an ice cube out of a cup full of water without touching it. Put an ice cube in a cup
filled with cold water. Lay a thread across the top of the cube, sprinkle with salt. Wait a minute and lift the
thread -- it will lift the cube!
Bernoulli’s Principle & Air Pressure Demonstrations
Blow a ping-pong ball out of a funnel.
Place a ping pong ball into a funnel. Try to blow it out of the funnel. Blow as hard as you can. What happens?
What happens if you invert the funnel while trying to blow? Does using a different sized funnel matter? What
about a different sized ball?
The Bernoulli Pop Can Ghost
MATERIALS:
1. Two empty soft drink cans.
2. About two dozen straight drinking straws.
PROCEDURE:
1. Spread the straws parallel to each other on the table and leave about 1/2 to 1 cm gap in between them.
2. Place the two cans upright about 2 cn from each other on the straws and show the students that they
can easily move closer or further apart.
3. Blow in between the two cans with a short hard puff.
4. Now spread the two cans about 5 cm apart. Blow harder.
5. Now place the cans about 20 cm apart. Take a deep breath and blow a constant stream of air on the
RIGHT SIDE of the LEFT can and move your head towards the right, while constantly blowing.
RATIONALE: This demonstration illustrated the Bernoulli principle. As the speed of air increases, the air
pressure decreases. Blowing in between the cans created a flow of air and thus a lower pressure compared to
the stationary air on the other side of the cans. It is this lower pressure that drew them together.
Theoretically, the cans could be placed an infinite distance away from each other and still be drawn
together, as long as a constant flow of air on one side of one can moves along with it, to move it to the other
can. Indeed, the faster the flow of air, the lower the pressure it exerts. But for the cans that were placed 20 cm
apart, only a constant flow that could move the can, was necessary.
APPLICATION: Aviation ( ie. airplane wings)
Why does that happen?
Place an index card on the table. Place a funnel over the card. What happens if you suck through the funnel?
What happens if you blow really hard through the funnel? (Both blowing and sucking reduces the air pressure
on top of the card. That means the room's normal air pressure is greater, causing the card to get pushed into
the funnel.)
Air pressure does that, too?
Tape two ping pong balls to two pieces of string . Hang them from a door jam so that the balls hang close to
each other without touching. Blow between them. What happens?
AFSE Science Demonstration & Activity Night
5/10/04
Are you thirsty?
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Put a drinking straw into a glass of water and sip.
Put two drinking straws into the glass and sip.
Now take one straw out of the glass and try to sip through both straws.
What happens when you put your fingertip over the end of the straw not in the glass?
Put two straws in the glass and one outside. Sip and see what happens.
What happens if you put your fingertip over the end of the straw and sip?
Now leave one straw in the water and two outside the glass. Sip.
Put your finger over one of the straws outside the glass and sip. Put your finger over both straws and sip.
Bubbles Aloft!
Use an index card as a fan to make a bubble stay aloft. Do you fan above, below, beside? Use what you’ve
learned about fast and slow moving air to make your decision!
The Coke Can Crusher
Materials: empty soda cans, hot plate (or Bunsen burner), tongs, pan of cool water
Put about a half inch of water into an empty soda can. Put the can on the heat source until the water boils.
You should wait until you see white steam coming out of the can. At that point, pick up the can with the tongs
and quickly invert it and place the top of the can into the pan of water.
The Balloon in the Flask
Materials: a 150-200 ml Erlenmeyer flask, balloon and hot plate.
Put a little water into the flask and heat it to a boil. After the water has boiled a few moments, take the flask off
the heat and immediately put the balloon over the flask's mouth. Let cool slowly at room temperature.
Websites with Science Demonstrations
http://www.csulb.edu/~lhenriqu/300demo.htm
http://nerds.unl.edu/pages/mamres/pages/demos/demo.html
http://nerds.unl.edu/pages/sciencedemos/index.htm
Sources of more Discrepant Events
http://www2.stephens.edu/brent/Kristen/Contents.asp
http://fcis.oise.utoronto.ca/~kperris/Disc.htm
Invitations To Science Inquiry, 2nd Edition, by Dr. Tik L. Liem
AFSE Science Demonstration & Activity Night
5/10/04