Material: small balloon, test tube, water, hot plate,
1. Stretch the opening of the balloon over the test tube so it
2. Fill the two beakers of water, placing one of them on the
hot plate which should be on medium high setting.
3. Place the test tube in the beaker on the hot plate. As the
water heats up observe what happens to the balloon. Place in cold
water beaker and observe what happens
1. Describe what happens to the balloon in the two cases.
2. Why does the balloon expand?
3. What happens to the balloon when the heat source is
4. Why do tire manufacturers advise checking tire pressure
when the tires are cold?
2-1) Telling Hot from Cold
Material: bowls of hot water, cold water, room
temperature water. Use 600 ml beakers for the bowls.
1. Obtain three bowls large enough to place a hand inside.
Fill one with hot water (not hot enough to burn), another with
cold water, another with lukewarm water.
2. Place the hot water on your left, cold water on your right,
and lukewarm water in the middle. Now place your left hand in the
hot water and your right hand in the cold water. Leave them there
for two minutes.
3. Pull your hands out and shake off the water. Now place them
both in the lukewarm water. Observe what happens.
1. Did you predict what would happen when you placed both
hands in the lukewarm water?
2. Describe your sensation when you placed both hands in the
3. Explain your sensation when both hands were placed in the
2-2) Cooling or Warming Breezes?
Material: two thermometers, small electric fan (brought
1. Take two identical thermometers and check that their
temperatures indicate the same. Place one thermometer in front of
an electric fan and the other thermometer near, but not in the
path of the air blowing through the fan.
2. Make and write down your prediction as to which thermometer
will be the coolest.
3. Let the fan blow for five minutes and read the temperature
of each thermometer.
1. What is your prediction for the coolest thermometer? Give
2. What was your experimental result? Does it make sense?
3. Why did the thermometers read the same?
4. Explain why we use electric fans to cool us in hot weather?
5. Predict what would happen in this experiment if the
thermometer bulbs were wet?
2-3) Bouncy, Bouncy, Oh My Rubber Ball!
Material: rubber ball (like a tennis ball), meter
stick, refrigerator freezer (or ice chest and sealable plastic
1. Find a hard even floor and measure a distance two meters
high. Mark the spot.
2. With the ball at room temperature drop the ball from the 2
meter height and note how far back up it bounces. Do the
measurement several times and take the average. Mark this spot.
3. Put the ball in the freezer for 30 minutes. If you don't
have a freezer place the ball inside a sealable plastic bag and
stick it in the ice chest. Do other activities while you wait for
the ball to get cold.
4. Make a prediction as to whether the cold ball will bounce
higher, lower, or the same.
5. Repeat step 2) with the cold ball and mark the new height.
1. Why do we take several measurements to determine the height
the ball bounces? Do the various measurements vary?
2. What prediction did you make as to what the cold ball would
do? Explain your prediction.
3. Explain why the cold ball bounced lower.
2-4) Expansion Joints. Why Do We Need Them?
Material: Tin or aluminum soda can, hammer, nail,
pliers, candle, matches.
1. Use the hammer to drive a nail into the top of the can. Use
the pliers to ease the nail out gently. Put the nail in the hole
again. Make sure the nail has a tight, not loose, fit in the can.
2. Take the nail out again gently and heat the nail using a
candle (or other flame source).
3. Try to put the hot nail into the hole.
1. What difference did you find when you tried to put the hot
nail into the can.
2. What caused the difference with the hot nail?
3. Explain why bridges have expansion joints and sidewalks
have spaces between their sections.