1752 – charges

1752 – Charges – Benjamin Franklin

In 1752 Benjamin Franlin through a series of experiment realized that electricy was not 2 different things, but one thing with 2 different charges.  He called one plus and the other negitive.  How he identified them, assign the negitive charge to the side with excess eletrons.  That is how a electron beame to be known as having a negitive charge.

Experiment I – Forms of electricity


Items needed:

  • 2 pieces of styrofoam (large enouph for a person to stand on)
  • 2 assistants
  • hair or fur
  • PVC pipe

The experiment:

  1. Have one person stand on a piece of styrofoam with the PVC pipe and hair/fur.
  2. Have another person stand on a piece of styrofoam close enouph so that their hands can touch.
  3. The 3 person should stand on the floor without shoe that would insultate them from the ground.
  4. Have the person with the PVC pipe rub the pipe with the hair/fur.
  5. Have the other person on the styro foam put their knuckles along the PVC pipe.  Repeat several times.
  6. Have each person Touch the person on the ground/floor.
  7. Repeat the process and have the 2 people on the styrofoam touch each other.
  8. Write down your observations.

Explanation:

When the person rubs the PVC pipe, the pipe becomes gains electrons and becomes negitively charged.  When the other person touches the PVC pipe, they get the electrons and then they are negitively charged.   The person who is rubbing the pipe will give up electrons and thus become positively charged.

Then they touch the they opposite charges attract the electons and the electrons jump from the negatively charged person to the positively charged person. 

When either person touched th person on the ground/floor electron either jumped from the person to the positively charged person or the eletrons jumps from the negitvely charged person to the person on the ground/floor.  This person on the ground/floor was neutral (evenly balenced), so could give up electrons or get electrons.   Since this person was on the ground and excess charge was absorbed in the earth.

Experiment II – Forms of electricity

Items needed:

  • Balloon 
  • thread
  • tape
  • clean glass jar
  • silk
  • hair or fur
  • PVC pipe

The experiment:

  1. Blow up the balloon and tie the end.
  2. Tie the thread to the balloon.
  3. Tape the other end of the thread to a table or some other object that the balloon can hang freely with touching anything.
  4. Rub the balloon with the hair or wool.
  5. Rub the glass jar with the silk.
  6. Slowly move the jar toward the balloon,
  7. Rub the PVC pipe with the hair/wool
  8. Slowly move the PVC pipe  toward the balloon,
  9. Write down your observations.

Explanation:

The hair/wool gives electrons to the balloon making it negatively charged and the glass jar gives up electrons to the silk making it negitively charged.  Just like like magnets opposites attract and the same charges repell.

Leave a Reply