Judy Lehmberg (FLC I) - Lee College

1. Weigh the piece of steel.
2. Put an amount of water equal to the weight of the steel object into the beaker.
3. Put the piece of steel into the water, and heat the container until it just begins to steam.
4. Immediately remove the piece of steel from the beaker, and put both the beaker of water and the piece of steel
onto the table. (Your results will be more accurate if you pour the hot water into a cool beaker at the same time
you put the steel on the table.)
5. Repeatedly touch both the water and the piece of steel until both are approximately the same temperature.
Keep track of how long it takes for each to cool.
Time for the water to cool = about 4 minutes
Time for the steel to cool = about 2.5 minutes
QUESTIONS:
1. Which substance cooled the slowest? (circle your choice)
the water should be circled Steel Water
2. Which substance would require more heat energy to heat it up? Remember that the amount of heat given off
by a substance equals the amount of heat absorbed by that substance when it was heated. (circle your choice)
the water should be circled Steel Water
3. We know that sitting in 70 degrees F water is more chilling to the body than sitting in room air at 70 degrees
F. Explain why.
The water would be more chilling because there are more water molecules in the bathtub than in the
surrounding air. As hydrogen bonds are forming they “pull” energy, in the form of heat, from their
surrounding environment. Your body temperature is higher than 70 degrees F, therefore the water gets energy
from you to form hydrogen bonds.
If you were made of steel, would it be more chilling or not? Explain.
It would be more chilling because steel does not form hydrogen bonds between its atoms. Hydrogen bonds help
living organisms maintain their body temperature.
4. Based on your experimental results, what do you conclude about the importance of the hydrogen bond on the
heating up of water?
It takes more energy to heat up water because water is held together by hydrogen bonds, but conversely, water
looses heat more slowly because of the hydrogen bonds. The hydrogen bonds between water molecules help
living organisms maintain the body temperature.
5. Is water a temperature-stabilizing substance for living organisms?
Yes, see answer to #4 above.
EVAPORATION OF WATER The heat of vaporization is the amount of heat energy required to vaporize a
substance (like water). We can estimate the heat of vaporization for water by comparing that process with what
32