Charged straw, paper bits

The idea

The force exerted by a charged body on another charged body or on an uncharged body, such as small pieces of paper, is electrostatic force; it is a non-contact force.

Straw and paper

A plastic straw is rubbed and then brought near small pieces of paper.

What will the paper pieces do?

• Move towards the straw
• Move away from it
• Stay exactly where they are

Rub and bring near

First rub the straw. Then bring it near the paper pieces.

A pull without touch

The rubbed straw became charged and pulled the paper pieces. The paper pieces had no charge, and the force still acted. This force acts even when the objects are not in contact.

The force exerted by a charged body on another charged body or an uncharged body, such as small pieces of paper, is called electrostatic force. It is a non-contact force.

Notes

The force of a charged body on another charged or uncharged body is electrostatic force. It is a non-contact force.

Check yourself

The force of a charged body on another body is called …

A rubbed straw pulls small pieces of paper. The paper pieces are …

Electrostatic force is a …

Will a straw that has not been rubbed pull the paper pieces?

• magnetic force. Magnetic force comes from magnets.
• muscular force. Muscular force comes from muscles.
• electrostatic force — correct. Yes!
• uncharged — correct. Yes!
• charged with the same charge. A charged body also pulls uncharged bodies like small paper pieces.
• magnets. The paper pieces are not magnets. They are uncharged.
• contact force. It acts even when the objects are not in contact.
• non-contact force — correct. Yes!
• force that needs a rope. It acts without any rope or touching.
• Yes, every straw does. The straw must be charged first by rubbing.
• Yes, if it is long. Length does not matter. Charge does.
• No, it must first be charged by rubbing — correct. Yes!