Static electricity

This practical lesson covers:

  1. How to charge insulating materials by friction

Investigating static electricity by charging insulated rods


Aim:

To investigate how insulating materials can be charged by friction.

Background information:

Insulating materials can become charged when they gain or lose electrons. This can happen when two insulating materials rub together and electrons are transferred from one material to another. This practical looks at how insulating materials become charged and ways we can observe the effect of an object being charged.

Variables:

  1. Independent variable - Insulating material  
  2. Dependent variable - Effect of charged insulators 
  3. Control variables - Method of charging by friction

Equipment:

  1. Gold leaf electroscope
  2. Polythene and/ or perspex rod
  3. Cloth

Method:

  1. Place the gold leaf electroscope on the bench and observe the deflection of the gold leaf. It should be in the uncharged position with the gold leaf hanging down. 
  2. Charge the perspex or polythene rod by rubbing against the cloth for approximately 1 minute. 
  3. Hold the rod near the top plate of the gold leaf electroscope and observe the deflection of the gold leaf.
  4. Turn on a tap with a thin stream of water. Bring the charged rod close to the stream of water and observe the deflection of the stream of water. 

What is the purpose of rubbing the perspex rod against the cloth?

to make it heavier

to cool it down

to charge it by transferring electrons between the materials

to heat it up

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What will the student observe when a charged rod is brought close to the top plate of an uncharged gold leaf electroscope?

the gold leaf will discharge

the gold leaf will be deflected

the gold leaf will fall off

a spark

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Static electricity is caused by the imbalance of charges. Which sub-atomic particle is transferred when a perspex rod is rubbed with a cloth?

alpha particle

proton

electron

neutron

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A student charges a perspex rod and places it near a gold leaf electroscope. The gold leaf is deflected by 20o. The rod is then rubbed for a further minute. Which of the following is the most likely angle of deflection when the rod is placed near the gold leaf electroscope again?

15o

25o

0o

20o

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When a balloon is rubbed against a jumper it sticks to the wall. Explain why.

electrons are transferred to the balloon when rubbed against the jumper. These are repelled by atoms in the wall.

protons are transferred to the balloon when rubbed against the jumper. These are attracted to atoms in the wall.

electrons are transferred to the balloon when rubbed against the jumper. These are attracted to the protons in the wall.

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