1. Hot and Cold Lab Recap

2. Boiling water graph
Time in seconds
TemperatureinC
At 100
degrees the
water begins
to boil.

3. What’s happening?
The water rises steadily until it reaches 100 degrees.
It levels out at 100
Why does the water temperature not rise above 100
degrees even if you keep heating it? (where is that
energy going?)

4. Boiling
Boiling is when you change a liquid to a gas by giving
it enough heat (ENERGY) so it can break free of the
attraction it has to the other water droplets.
When water reaches 100 degrees, some of the water
molecules get enough energy to turn into a gas. If
you kept heating it, more and more of the liquid
would be boiling and becoming a gas.

5. Freezing water graph
Time in seconds
TemperatureinC
At zero
degrees the
water begins to
freeze
When the
water is totally
frozen the
temperature
begins to drop
again

6. What’s Happening?
When you cool the water down you are taking energy
from it! (Remember, the salt melts the ice on the
outside, so it takes energy to turn the ice into a
liquid).
Why does the temperature flat line and then drop?

7. Freezing
The temperature drops once the ice is frozen solid.
Zero degrees is when the water begins to turn to ice.
When it starts dropping again the ice is frozen solid
and the energy that is being stolen can go towards
lowering the temperature of the solid.