Lesson 7 ā€” Activity 1: Absorbing and Losing Heat



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In L6 ā€” A3, you learned that water moderates the temperature of the land near it. In this activity, you will see another reason why this happens, while learning that different materials absorb heat at different rates. This is called heat absorption.  

                                  
 

Different substances require different amounts of thermal energy (heat) to raise their temperature the same amount. This is true for all substances. Every substance requires a unique amount of heat gain or loss to change its temperature.

 Specific heat capacity is the amount of heat required to change the temperature of a substance. As water requires more time to boil than does alcohol, you might conclude that water requires more heat than alcohol to raise its temperature. In other words, water has a higher specific heat capacity. Your conclusion would be correct.


 Specific heat capacity is measured in joules per gram degrees Celsius. This is often written as:
J/gā€¢Ā° C
 
Here's an example:

The specific heat capacity for water is 4.19 J/gā€¢Ā° C. This means that:


  • one gram of water absorbs 4.19 joules of heat to raise its temperature 1Ā° C
  • one gram of water loses 4.19 joules of heat to lower its temperature 1Ā° C


Click on the Play button to watch a video that further explains specific heat capacity.



The table below lists heat capacities for different substances.


You learned from the video and noted on the table above that the specific heat capacity of water (4.19) is a lot higher than that of sand (0.66). Again, it takes more energy to increase the temperature of water than it does to increase the temperature of sand. Think of being at a beach on a hot, sunny day. It's no wonder the sand on the beach is much warmer than the shallow water nearby.

 

You know that oceans moderate land areas near shore. You have seen in this activity that water has a high specific heat capacity compared with other substances. Oceans store more heat energy, or thermal energy, than you might think.

Add this knowledge to what you know about sea breezes and land breezes. With its large specific heat capacity, water can absorb, store, or release much more thermal energy than land can. That is another reason for land heating and cooling quicker than lakes and oceans.

Specific heat capacity affects climate in other ways:
  • On a hot day, water will absorb heat. This slows the rise of temperatures in the surrounding area.
  • At night, water will release heat. This slows cooling in surrounding areas.


 

Self-Check

Try This!

Try the questions below on your own first and then click on the tab to check your answers!

Decide if the following statements are true or false.

1. Different substances usually do not require different amounts of thermal energy (heat) to raise their temperature the same amount.

2. Specific heat capacity is the amount of heat required to change the temperature of a substance.

3. Specific heat capacity is measured in joules per gram degrees Celsius.

4. The specific heat capacity of sand is a lot higher than that of water.

5. With its large specific heat capacity, water can absorb, store, or release much more thermal energy than land can.



1.  False. Different substances require different amounts of thermal energy (heat) to raise their temperature the same amount.
2. True
3. True
4. False. The specific heat capacity of water is a lot higher than that of sand.
5. True