Activity 6.1.1
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1) Hand Warmer: In your groups
activate the metal disk inside the
liquid solution. What questions do
you have about the hand warmer?
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2) Examine the opened cold pack that your
teacher will provide. Activate one cold pack
per class and pass it around the room. What
do you notice? What questions do you have
about the cold pack?
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3) Place a small amount of calcium chloride
solid into 15-20 mL of cold water and stir.
Feel the beaker and remember your
observations. After discussing your questions
as a class, answer the following based on your
experience . . .
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4) Which experiences (hot pack, cold pack,
CaCl2 beaker) made your hands feel warmer?
Hot pack, then CaCl2 beaker
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5) Which way is the heat energy moving? Imagine you are
holding the cold pack, hot pack, or solution. Draw an arrow
indicating whether heat moves from your hand to the object
or from the object to your hand.
Heat Pack
CaCl2 beaker
Cold Pack
Hand
Hand
Hand
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6) In which of the 3 scenarios did the heat travel from the
system to your hand?
Hot pack, & the CaCl2
7) In which of the 3 scenarios did the heat travel from your
hand to the system?
Cold pack
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8) If you leave the hot pack over night, will it still be hot
tomorrow? Why or why not?
No, it will have given off heat until it
equalized with the room.
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Ice Cube Melting on a Counter Top:
1. Draw arrows showing which direction heat is being
transferred, into, or out of, the ice cube.
2. Where exactly is the heat coming from?
The surroundings
3. How are the molecules of H2O in the puddle of water
different from the molecules of water still in the solid ice
cube?
They are moving faster
4. When the ice cube melts, is it releasing heat or taking
heat from the environment? Taking heat from the environment
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Water Freezing in an Ice Cube Tray:
5. Draw arrows showing which direction heat is being transferred
when the ice cube tray is placed in the freezer. Is heat being
transferred into or out of the water as it freezes into ice?
6. Is heat being transferred into or out of the air directly around the
ice cube tray?
Heat is transferred out.
7. In order to cool things in a refrigerator, heat must be transferred
away from the food. Where do you think this heat ends up going?
Outside of the fridge.
8. When water freezes, is it releasing heat or taking heat from the
environment?
Releasing heat.
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Making an NH4Cl Solution:
9. The temperature decreases when you dissolve solid NH4Cl in
water. What would you feel if you held this beaker?
It would feel cold. (Your heat leaves you).
10. Do you think this process would be used to create a cold pack to
reduce swelling or a hot pack to increase circulation? Explain.
Cold pack.
11. In the process of dissolving solid NH4Cl in water, describe the
direction in which heat is moving.
Endothermic, heat is transferred from the environment to
the system.
12. Do you think the thermometer is part of the system or
surroundings?
Surroundings.
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13. When the temperature of the thermometer goes down, do you
think heat is going into the thermometer or out of the thermometer?
Out of the thermometer.
14. If the thermometer is put in a reaction and ∆T is positive, did heat
go into the thermometer or out of the thermometer?
Into the thermometer.
Making Sense
What does it mean to say that something is hot?
It will transfer energy TO you.
What does cold mean?
It will transfer energy AWAY from you.
Can you transfer cold? Explain.
No, heat can only move from warmer to
cooler objects.