Lab #7 – Heating Up and Cooling Down

Lab #7 – Heating Up and Cooling Down

Do you remember how long it took for a cup of hot chocolate to cool before you could take a sip? The hotter the chocolate, the longer it seemed to take to cool.

Problem

 How does the temperature of a liquid affect how quickly it warms or cools?

Hypothesis

                       

Materials

3 beakers

3 thermometers

Stopwatch

Ice

Hot plate

  

Procedure

1. Use the data table to record the temperature of water in three beakers every minute from 0 to 10 min.
2. Fill one beaker with 100 mL of water. Place the beaker on a hot plate and bring the water to a boil. Carefully remove the hot beaker from the hot plate.
3. Record the water temperature in your data table at minute 0, and then every minute for 10 min.
4. Repeat step 3 starting with water at room temperature and ice water.

 Results

Ice Water

Time (min.)	Temperature ('F)	Temperature ('C)
0	32’F	0’C
1
2
3
4
5
6
7
8
9
10

  

Room Temperature water

Time (min.)	Temperature ('F)	Temperature ('C)
0
1
2
3
4
5
6
7
8
9
10

  

Boiling Water

Time (min.)	Temperature ('F)	Temperature ('C)
0	212’F	100’C
1
2
3
4
5
6
7
8
9
10

  

Analysis

1. Using the ‘F/’C conversion formula, convert your remaining temperatures and fill in the data table.  °C  x  9/5 + 32 = °F

(°F  -  32)  x  5/9 = °C

2. Construct a line graph for each set of data: a graph for ice water, one for room temperature water, and one for boiling water; use only temperatures in Fahrenheit! *Label x-axis, y-axis, and title*

3. Combining the data from all of your results, construct a fourth line graph; use a different color for each line.  Remember to include a key. Use only temperatures in Celsius!   *Label x-axis, y-axis, and title*

4. Calculate the rate of heating or cooling for the water in each beaker by subtracting the initial temperature of the water from the final temperature and then dividing by 10 min.  Do this for each set of data i.e. ice, room temp., boiling

Rate=Final (10 min.) Temp. – Initial (0 min.) Temp.

                           10

5. Infer from your results how the difference between room temperature and the initial temperature of the water affected the rate at which it heated up or cooled down.

6. What happened to the temperature of the boiling water?  What happened to the temperature of the ice water?  Do you think there will be a temperature at which they would eventually meet?  If so, where do you think it will be?  If not, why not?

7a. What was the independent variable?

7b. What was the dependent variable?

7c. What should remain constant?

Conclusion