Chapter 8: Energy and Energy Resources Section 1: What is energy?

What is energy?

A. Energy – is the ability to cause a change (or the ability to do work) 1. The SI unit for energy is the joule (J) 2. There are many different forms of energy, but most are types of kinetic or potential energy.

B. Energy from motion is kinetic energy. 1. Kinetic energy increases as an object moves faster. 2. Kinetic energy increases as the mass of an object increases.

C. Energy stored in an object due to its position is potential energy. 1. Potential energy increases as the mass of an object increases. 2. The higher above Earth’s surface an object is, the more gravitational potential it has.

D. Other forms of energy… 1. Thermal energy – the sum of the kinetic and potential energy of all the particles in a substance. a. All substances have thermal energy because their particles are always moving. b. Thermal energy increases as temperature increases.

D. Other forms of energy… 2. Chemical energy – energy stored in chemical bonds. a. Chemical energy is a type of potential energy. b. The energy stored in food and batteries is chemical energy.

D. Other forms of energy… 3. Radiant energy – energy that travels in the form of waves. - Examples are: light, microwaves, and radio waves.

D. Other forms of energy… 4. Electrical energy is energy carried by an electric current. 1. Any machine you plug in uses electrical energy. 2. All electrical devices change electricity into other types of energy.

D. Other forms of energy… 5. Nuclear energy – is energy stored in the nucleus of an atom