1Two invisible things
Tiny charges, and a tug you can't see
Everything is built from tiny bits, and some of them carry a hidden charge. Here are the two ideas you need:
Rubbing moves charges
Rub two things together and tiny charges scrape off one and pile onto the other. You can't see them — but watch the dots jump across.
Opposite charges pull
A blue charge and an orange charge pull toward each other across empty space — an invisible tug, no string needed.
2The same balloon, two ways
Loaded or empty?
Rubbed up, covered in charges
After rubbing, the balloon carries a pile of extra blue charges. They're invisible, but they're there — ready to tug on whatever's nearby.
Same balloon, no extra charges
Take the charges away and you've got a plain old balloon again — exactly the same surface, but with nothing to tug. The only difference between the two is something you cannot see.
3Your turn — rub it up
Load the balloon and hold it to the wall
Drag the rub slider to scrape more charges onto the balloon. The more blue charges it carries, the harder it pulls the wall's orange charges up to meet it — and the higher it can cling.
4Now try to switch it off
Touch it to a metal pole 🔌
Here's the test. Rub the balloon so it sticks. Then touch it to a metal pole, which lets charges flow away. Try the wall again — what happens?
Guess before you find out
You rub a balloon so it sticks to the wall. Then you touch it to a metal pole and try again. Does it still stick?
5So is it a forever trick?
Not quite — the charge leaks away
Loaded up, it pulls hard on the wall and hangs there all on its own — no glue, no tape.
Touch metal and the stick vanishes at once — clear proof it was never glue, just charge.
Rubbing doesn't make a balloon sticky — it loads it with invisible charges, and those charges pull on the wall. Take the charges away and the balloon falls. It was never glue.
Psst, grown-ups: rubbing transfers electrons between materials (the triboelectric effect), leaving the balloon with a net negative charge. Held near a neutral wall, that charge polarizes the wall's molecules — pulling slight positive charge nearer and pushing negative away. Because the attracting charge ends up closer than the repelling charge, the net electrostatic force is attractive and can exceed the balloon's weight. The balloon stays up until the charge bleeds off through the air (faster when humid) or to a conductor such as a grounded metal pole.