- Matter is composed of atoms, which have negatively charged electrons spinning around a positive nucleus. When electrons are transferred from one object to another, the object receiving the electrons becomes negatively charged while the object loosing the electrons becomes positively charged. When two objects with like (the same) charge come close to each other, they repel each other. When two objects with opposite charges come close to each other, they attract each other.
- In this lab, you will observe these attracting and repelling forces.
MATERIALS NEEDED:2 round 9 inch balloons
Masking tape
2 one-meter pieces of string
Open door frame
Marking pen
clean, dry, oil-free hairPROCEDURE:
Inflate both balloons and tie their ends. Use the marking pen to label one balloon A and the other B.
Attach one piece of string to the end of each balloon
Tape the free ends of the strings to the top of a door frame so that the balloons hang about 20 cm apart.
Stroke balloon A on your hair about 10 to 15 times and gently release it. What do you observe happening?Now stroke both of the balloons on your hair about 10 to 15 times and gently release both balloons. What do you observe happening this time?DISCUSSION:
- When balloon A was rubbed on your hair, it picked up electrons from the hair and became negatively charged. When it came close to balloon B its negative charges actually repel the electrons in the atoms of balloon B. This causes the surface of balloon B to be more positively charged. Each balloon now has a different charge, so they are attracted to each other.
- When both balloons are rubbed on your hair, they both pick up electrons from the hair and both become negatively charged. Because both balloons have like charges, they repel each other.
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- In this lab, you will observe these attracting and repelling forces.
OBSERVING THE ATTRACTING AND REPELLING FORCES
OF ELECTRICAL CHARGES
INTRODUCTION: