MAKING OBJECTS ATTRACT OR REPEL 
Tie an 8-inch length of string around a plastic spoon, and label the spoon #1. Suspend it from a ruler or stick secured on a table so that it hangs on its side.

Label a second plastic spoon #2, and bring it close to the bowl of the first spoon until the two spoons almost touch.

Now rub both sides of the bowl of spoon #1 several times with a piece of sandwich wrap, then rebalance the spoon. Rub #2 the same way, then bring the bowls of both spoons close together. (They should move apart.)

Why is this?

The particles that make up atoms have electrical charges. Scientists say that each proton has a positive charge, and each electron has a negative charge.

When plastic spoons are rubbed with sandwich wrap, electrons from the atoms in the spoons are transferred to the wrap, leaving the spoons with more protons (positive charges) and giving the wrap more electrons (negative charges).

Therefore, when the two positively charged spoons are brought together, they repel each other.

Now number two balloons, and hang balloon #1 from a ruler with a string. Rub the  balloon with a piece of wool. (Try not to make too much wind near the balloon, because wind blowing around the balloon can make it difficult to observe what happens.) 

Rub balloon #2 in the same way, and bring the balloons together. (They will repel each other.) When balloons are rubbed with wool, electrons are brushed from the atoms in the wool and are transferred to the balloons, leaving the wool with a positive charge and giving the balloons a negative charge. Next, rub spoon #1 with sandwich wrap, and make sure it is balanced. Then rub balloon #2 with wool, and slowly bring it close to the spoon. (The objects will attract each other.) From these tests, you will realize that when their electrical charges are alike, objects repel each other; when their electrical charges are different, objects attract each other. In the atom, the electron is attracted to the proton because their charges are not alike. Is this what people mean when they say that "opposites attract?"