Lesson 4 Thermal Energy
Thermal Properties
The differences in how substances absorb thermal energy can have a large impact on climate.
| Compound |
Specific Heat Capacity
(J/g•°C) |
|---|---|
| water | 4.19 |
| methanol | 2.56 |
| air | 1.01 |
| aluminium | 0.897 |
| soil | 0.85 |
| stainless steel
|
0.502 |
Every substance has different thermal properties. The thermal property we will focus on in this course is how substances absorb thermal energy differently. Some substances can absorb lots of thermal energy very quickly, while others absorb it more slowly. These same substances will then release the thermal energy just as fast or as slow as they absorbed it. This property is called a substance’s specific heat capacity, and it is the amount of energy needed to raise 1 g of a substance 1 ˚C. Remember, thermal energy always moves from an area of high thermal energy to an area of low thermal energy.
Water has a specific heat capacity of 4.19 J/g•˚C. This means it takes 4.19 J of energy to raise 1 g (or 1 mL) of water 1 ˚C. Water has a relatively high specific heat capacity, while aluminium has a lower specific heat capacity, just 0.897 J/g•˚C. This means it takes only 0.897 J of energy to raise 1 g of aluminium 1 ˚C. Generally speaking, the hydrosphere has a much higher specific heat capacity than the lithosphere does. This is why cities that are close to large bodies of water have a different climate than cities surrounded by land, even when they are in a similar biome.
Water has a specific heat capacity of 4.19 J/g•˚C. This means it takes 4.19 J of energy to raise 1 g (or 1 mL) of water 1 ˚C. Water has a relatively high specific heat capacity, while aluminium has a lower specific heat capacity, just 0.897 J/g•˚C. This means it takes only 0.897 J of energy to raise 1 g of aluminium 1 ˚C. Generally speaking, the hydrosphere has a much higher specific heat capacity than the lithosphere does. This is why cities that are close to large bodies of water have a different climate than cities surrounded by land, even when they are in a similar biome.
Since water has such a high specific heat capacity, it takes a lot of energy to raise the temperature of water. This means water takes longer to heat up and cool down compared to other substances. When water does cool down, a lot of energy is released into the surrounding environment. Because it takes so long for water to heat up or cool down, it actually helps to level out any variations in temperature for cities located nearby. If the air temperature is very cold, the thermal energy will leave the water and heat up the air and land. If the air temperature is very warm, the water will absorb the thermal energy and cool down the air and land. The water will do this with very little change to its own temperature. If the water itself is cooler (such as the Atlantic Ocean), it will create a cooler climate, as it will absorb more thermal energy. If the water is warmer (such as the Pacific Ocean), it will create a warmer climate, as it will release more thermal energy.
Water’s specific heat capacity plays a very large part in the climate of the areas surrounding large bodies of water.
Water’s specific heat capacity plays a very large part in the climate of the areas surrounding large bodies of water.
D4.3 Inner Harbour at Victoria BC
Did You Know?
D4.4 A greenhouse in the winter
Large containers of water are sometimes placed in greenhouses over the winter to help prevent the plants from freezing. During the day, the sun heats the greenhouse and the water absorbs the excess heat. At night, the water cools and releases large amounts of thermal energy into the air, warming the greenhouse up.
Read This
Please read pages 377 and 378 in your Science 10 textbook. Make sure you take notes on your readings to study from later. You should focus on what specific heat capacity is and how it affects climate. Remember, if you have any questions or you do not understand something, ask your teacher!
Practice Questions
Complete the following practice questions to check your understanding of the concept you just learned. Make sure you write complete answers to the practice questions in your notes. After you have checked your answers, make corrections to your responses (where necessary) to study from.
- Explain what specific heat capacity is.
Specific heat capacity is the amount of energy it takes to raise 1 g of a substance 1 ËšC.
-
How does specific heat capacity affect climate?
Water has a relatively high specific heat capacity, so it takes lots of thermal energy for water to heat up or cool down. This means it can transfer or absorb lots of thermal energy from the air and land around it without changing its own temperature very much. This makes the land and air around water have less variation in temperature. It also means cooler water makes cooler climates, while warmer water makes warmer climates.