http://www.ck12.org Chapter 18. Thermal Energy
FIGURE 18.15
Thermal energy is converted to the kinetic energy of the moving piston inside the cylinder. The moving piston, in
turn, can be used to turn a turbine or do other useful work.In a car, the piston is connected by the piston rod to the crankshaft. The crankshaft rotates when the piston moves
up and down. The kinetic energy of the moving crankshaft is used to turn the driveshaft, which causes the wheels of
the car to turn. Most cars have at least four cylinders connected to the crankshaft. Their pistons move up and down
in sequence, one after the other. You can watch animations of internal combustion engines in action at these URLs:
Lesson Summary
- Two common home heating systems are hot-water and warm-air heating systems. They burn fuel for thermal
energy and transfer the energy to water or air. The heated water or air circulates throughout the house,
transferring thermal energy to the air in each room. - Cooling systems such as air conditioners and refrigerators reverse the normal direction of heat flow by doing
work. For example, a refrigerator uses a refrigerant to transfer thermal energy from a cool refrigerator to a