1. Electric Current How is water like electricity?

2. What is current? Water tends to flow from high places to low places, due to it’s potential energy or the effect of gravity. Electricity acts in the same manner. Electrons will flow from a place with a negative charge to a place with positive charges (Opposites attract)

3. What is current? Electric Current (I) is the net movement of electrons in a single direction. Electric current is measured in amperes or amps (A) 1 ampere = 6250 million billion electrons or 6.24 X 10 18 (coulomb) flowing past a point every second [1 A = 1 C/S]

4. What creates the current? With water, a difference in height would make the water move. With electric current, you need a power source to provide a voltage difference.

5. What is a voltage difference? The voltage difference (V) is the difference in the voltage or the electric potential energy. Think of it like an electric pressure. With a battery, electrons are on one end, the negative end. They want to travel to the positive end of the battery. Voltage is measured in volts (V) [ 1 volt = 1 joule/coulomb ]

6. What makes the light bulb glow? Like water current, electric current can be slowed down by bumping into things The part of the circuit which is inside of the light bulb is a thin wire called a filament. This filament resists the flow of electrons; The electrons bump into the molecules in the material and electrical energy is converted into thermal and then radiant energy (glow). The filament has a high resistance.

7. What is resistance? Resistance (R)- the tendency for a material to oppose the flow of electrons. Conductors have less resistance than insulators. (Copper is an excellent conductor, it has a low resistance) Resistance is measured in Ohms (Ω)

8. Quiz What keeps the current flowing in a circuit? The voltage difference of the battery What makes a light bulb glow? The resistance of the filaments in the bulb How is water like electricity? It has a current (I), requires a difference in energy to keep moving (V) and can be slowed down by objects in its path (R).

9. Water Analogy Animation http://www.youtube.com/watch?v=j8Tyyg Wl9nQ