1. Renewable energy source: a source of energy; such as water, which can be replaced or restocked in a human lifetime.
2. Non-renewable energy source: a source of energy; such as fossil fuels and uranium, which cannot be replaced or restocked in a human lifetime.
3. Negative charges: the type of electrical charges that can be rubbed off a material; negative charges are associated with electrons.
4. Positive charges: the type of electrical charges that are left behind when negative charges are rubbed off a material; positive charges are associated with protons.
5. Electrically neutral: an object that has an equal number of positive charges and negative charges; this object is not electrically charged.
6. Conductor: a material that lets heat and electricity move through it easily; conductors are usually metals.
7. Conductivity: describes how easily a substance lets heat or electricity move through it.
8. Insulator: material that does not allow heat and electricity to move through it easily; insulators are often made of plastic or rubber.
9. Charging by contact: causing a neutral object to become charged by touching it with a charged object; for example, getting a shock when you touched a charged doorknob.
10. Electroscope: a device for testing an object to find out if it is charged.
11. Charging by induction: causing a neutral object to become charged by bringing a charged object near to you, but not touching, the object; for example, having your hair stand up when you bring a charged comb near to, but not touching it.
12. Discharged: state of an object when it has lost its excess charge; for example, a doorknob with excess negative charge becomes discharged when it passes the excess charge to the hand of someone who touches the knob.
13. Grounding: connecting a conductor to Earth’s surface so that charges can flow safely to the ground; a metal rod is used to ground the metal parts of large tank trucks while they are refuelling.
14. Source: a material whose energy is used to create electricity; moving water, fossil fuels (coal, oil, natural gas), uranium, wind, and the Sun are all sources of electrical energy; also, the device that supplies electrical energy to operate any electrical device; for example, a battery or an outlet.
15. Potential difference: used to describe the amount of energy a source can provide; the potential difference across a source is the difference between the energy of a unit of charge entering one end of a source, and the energy of a unit of charge leaving the other end of the source; potential difference is measured in volts, so its measurement is called voltage.
16. Current: a flow of electrical charges; an electric current carries energy from a source (such as a battery) to an electrical device (such as a flashlight) along wires; electric current is measured in amperes; this measurement represents how many units of charge pass a point every second.
17. Ampere: the unit of measure that describes the amount of current flowing through a wire in an electrical circuit; ampere is abbreviated as amps.
