When cars are built using assembly lines, a special method is used to paint them. Small droplets of paint are charged magnetically and are then sprayed onto the car.

We are trying to do something similar today, but less messy! And we will see that paper can stick to a balloon without any glue.

What you need:

• Scrap paper
• Balloons
• Drinking straw
• Scissors

What to do:

1. Cut the paper into tiny pieces a few millimetres big. The easiest way to do this is to cut the paper into long thin strips, then gather the strips together and snip them into tiny squares.
   
   
2. Gather the paper pieces into a pile on a table.
   
   
3. Blow up the balloon, then charge it by rubbing it vigorously on a woolly jumper or your hair.
   
   
4. Hold the charged balloon a few centimetres in front of the pile, and about 5cm above the table.
   
   
5. Blow through the straw very gently down onto the pile of paper. This will force the squares forward and up into the air.
   
   
6. As the squares float past the balloon, they will be drawn to it and stick on.

Why?

All substances contain electrically negative charged particles called electrons. When two different substances are rubbed together, some of the electrons may move from one to the other. This creates a charge imbalance, with one substance negative and the other one positive.

Like magnetic north and south poles, positive and negative charges attract each other. When you rub the balloon on your hair or jumper, electrons are knocked off and end up on the balloon, making the balloon electrically negative.

The tiny paper squares are uncharged, but in comparison to the balloon they are more positive. The squares are therefore attracted to the negatively charged balloon, and as they float past they are drawn to the balloon and stick to it.

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