Measurement of Heat Transfer Lab

Measurement of Heat Transfer

    The first law of thermodynamics says that heat added into a system changes into an equal amount of some other energy.  It is based on the law that says energy cannot be created or destroyed.  It can only change forms.  You can understand the law of thermodynamics if you understand a car engine.   Gasoline is burned.  The energy in its bonds is released.  That energy causes the gases in the combustion chamber to explode.  The explosion forces a piston to move.  The piston does work.  The heat energy put into the engine equals the increase of temperature inside the engine plus the work that the piston did.

Draw and explain the heat transfer in a car engine.  

    This next activity is a simpler way to show the law of conservation of energy.  You will measure the amount of heat lost by hot water and the amount of heat gained by cool water.  You will mix different amounts of hot and cold water together to determine their final temperature.You will mix different amounts of hot and cold water together to determine their final determine.

Procedure:

1. first write an objective and a hypothesis.

2. Put 60 mL of hot water in your cop. measure the temperature and record in your data table. Measure 60 mL of cold water and record temperature, then add to hot water. Stir the water gently until the temperature remains steady and then record in your table.

--Repeat the experiment with 30 mL of hot water and 60 mL of cold water.

Volume		Starting Temperature		Final Temperature	Temperature Rise	Temperature Drop
cool water	hot water	cool water	hot water	mixture	cool water	hot water

Answer the following questions in your conclusion:

3.  When you mixed equal volumes of hot and cold water, what happened to the temperature?  How did the temperature rise of the cool water and temperature drop of the hot water compare?

4.  Was the result what you expected?  What does this tell you about energy transfer in this activity?

5.  When you mixed only 30 mL of hot water with 60 mL of cool water, how did the temperature rise of the cool water and the temperature drop of the hot water compare?  How would you explain your results?

6.  Explain the First Law of Thermodynamics.  How does your experiment support the Law of Thermodynamics.  Describe data that support the Law.