07/09/09

Electricity

Is a kind of energy .it has two different kinds of: positive charge and negative charge.

+ And+=repel

-And - =repel

+ And - =attract

Before rubbing, the pen has equal numbers of positive and negative charge. This charges balance each other. The pen is electrically neutral.

When the pen is rubbed with other thing, negative charges travel from the other from the other thing to the pen. The pen now has more negative charges have left the other thing; it now has more positive charges than negative .it has become positively charged.

Atoms contain negatively charged particles =electrons

Positively charged particles=protons

Neutral particles = neutrons

14/09/09

Moving charges

You can do some hair racing experiments with van de graaff generator.this is a machine for building up and storing electric charges when it is switched on,negative charges collect on the dome.the dome becomes negative charges .

Storing charge:if you stand on a prece of plastic and touch the dome,you body connects extra negative charge from the dome.thats when your hair stands on end.each hair becames negatively charge the hairs repel each other .

Losing charge:if you then touch a water tap,your body loses this charges you hair goes bag to normal .the charges flow for body a long the water pipe to the earth you can feel them go your fingers tingle.

Flow a charges: there are two good ways of chowing this flow of charge you can connect a neon bulb between the generation and the water tap.the bulb glose as the charges flow through it you can also connect in a meter wich measure small electric currents the flow of charge through the meter makes the meter middle move.

Atoms contain negatively charged particles: electrons

Positively charged particles: protons

Homework

For Wednesday 16 September/09 written on sheets of paper.

1. What does a van the Graff generator do?

Cargando energia negativa

2. Why does your hair stand on end when you use the generator to charge yourself up?

Carga energia negativa

3. Why does your hair go back to normal when you touch a water top?

4. What is an electric current? Es un flujo de cargas electricas

5. Why should you stand on plastic or rubber if you want to charge yourself up? El plastic es un aislante