When walking on the beach on a hot summer day, you might make an observation about the heat capacity of two substances. Energy from the Sun is being absorbed by both the ocean water and the beach sand at the same time. You know that walking across the sand can burn your feet in the midday Sun. At the same time, the ocean water is cool and refreshing. Why do the substances heat up at different rates? The answer is that both substances have a different heat capacities. A substance's ability to absorb energy before it changes temperature is its heat capacity. Scientists have defined specific heat capacity (Cp) as the amount of energy one gram of a substance needs to absorb in order to raise its temperature one degree Celsius.
When you are at the beach in the summer, the sand has a lower heat capacity than the ocean water. This means that the beach sand will heat and cool at much faster rates than the water. The water will take a long time to warm up, retaining its heat over time. Also, a greater mass of a substance requires a greater amount of energy to raise the temperature for the entire substance. Think about the time it would take to bring a cup of water to a boil versus and entire pot of water. The cup of water would take much less time to come to a complete boil.
Calculating Specific Heat
Specific heat is calculated using the specific heat formula. With this formula, you can solve for heat, specific heat, temperature change, and mass. When you are completing these calculations, it is very helpful to make a list of what variables are known and what variables are unknown. View this presentation to learn how to calculate problems involving specific heat.
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Specific Heat Capacity Review
Now that you have learned how to calculate specific heat, complete this non-graded activity to check your knowledge. Read each problem, determine the known and unknown variables, and solve for the solution. Enter your answers in the blank spaces provided and click SUBMIT to check your responses. Click on the interactivity thumbnail, and then click NEXT to get started.