CK-12 Physical Science - For Middle School

18.3. Using Thermal Energy http://www.ck12.org

FIGURE 18.16

Combustion within the closed cylinder

pushes the piston downward. The moving

piston turns the crankshaft.

warm room.

• A combustion engine is a complex machine that burns fuel to produce thermal energy and then uses the thermal
  energy to do work. Combustion engines may by external or internal combustion engines, depending on where
  the fuel is burned.

Lesson Review Questions

Recall

1. How does a hot-water radiator transfer thermal energy to the nearby air?


2. What is a refrigerant?


3. What is the direction of thermal energy flow in a refrigerator?


4. How does a combustion engine use thermal energy?

Apply Concepts

5. Create a sketch to model a home heating system. You may model either a hot-water system or a warm-air
   system.