Physics P4: Static Electricity

Static Electricity are charges that are not free to move. They build up in one place and eventually cause a shock or a spark when they move.

Static is caused by friction.

• Two insulating materials rubbed together- electrons are scraped off one on to the other. One of the materials then has a positive charge, and the other negative.
• Which is which depends on the materials involved.
• Electrically charged objects attract small neutral objects, eg. balloon and paper.

ONLY ELECTRONS MOVE, NEVER THE POSITIVE CHARGES.

Electrostatic charges are only ever caused by the movement of electrons. Positive charges are caused by electrons moving away elsewhere. Acetate rods - from the rod to the duster. Polythene rods - from the duster to the rod.

Charged conductors can be discharged safely by connecting it to the ground with a metal strap. The electrons will flow down the ***** if it's negatively charged, and flow up the ***** if it's positively charged.

Dust particles are charged and are attracted to opposite charges. Items in the home are insulators are easily charged, like tv screens. The dust is attracted to them, making cleaning difficult.

Walking along a nylon carpet wearing shoes with rubber soles, a static charge builds up. If you touch a metal door handle the charge flows to the conductor and you get a shock.

Synthetic clothes are rubbed against each other or pulled over your head, electrons get scraped off. The two materials attract each other and therefore stick to each other.

Static builds up when: Grain shoots out of pipes, fuel flows out of a filler pipe and paper drags over rollers.