To find the relationship of charges and the forces between charged objects by
charging by friction, charging by grounding, and charging by induction.
Part 1: Place some paper bits on a table, and rub a plastic straw on your hair. Bring the straw near
the paper bits, and record the results. Repeat this process with a plastic cup instead of a plastic
straw. Next, blow up a balloon and rub that in your hair. Bring the balloon near the paper bits,
and then bring your hair near the paper bits. Record those results. Now, tape a long piece of
thread to the bottom of a plastic cup, and tape the other end of the thread to the ceiling so that the
cup hangs. Rub the hanging cup with your hair, and rub a different plastic cup in your hair as
well. Bring the two cups together, and record the results. Now rub a picnic plate against an
acrylic plastic sheet. Bring the plate near the charged, suspended cup, and then bring the acrylic
sheet near the hanging cup, and record those results. Then hang two cups from the same point on
the ceiling and charge both of them, and record the results. Next, rub half of a picnic plate with
fur and bring it near the hairs on the back of your hand, and record whether you could detect
which part of the plate was charged. Then, charge a blue foam pad by rubbing it with fur, and
charge a picnic plate likewise. Bring them close together, and record whether a repelling force is
there or not.
Part 2: Stick a piece of tape about 30 cm long to a tabletop as a working surface or base tape.
Take about a 10 cm piece of tape, and make a tab by folding the first cm of tape on one end
sticky side together. Stick the tape to the base tape and press it down. Now peel the short tape off
the tape, and record which sides of the tape attract paper bits. Now roll a piece of paper to form a
tube, and bring it near the tape, and record what happens. Make a second short tape strip, and
press them both down on the base tape separately, and then peel them loose. Try bringing them