Clickory

Why does rubbing a balloon on your hair make it stick to the wall?

Keep going

What else makes you wonder?

Could the charged balloon pull on a skinny stream of tap water — without touching it?

The pull reached the wall without touching it — and water is free to swerve. Predict which way a skinny stream bends, then try it at the sink.

Right after you rub, why does your hair reach up toward the balloon like it misses it?

Rubbing scraped blue charges off your hair onto the balloon. Think about what your hair is left with — and what the book says different charges do across a gap.

Why does the balloon trick work great on a dry winter day but barely at all in sticky summer air?

Damp air acts a little like the metal pole. If wet air can slowly sneak the balloon's charges away, how long can the invisible grip last?

ages 8–11Why does a bulb only light up when the wire makes a full loop? Open ages 8–11Why is it so much harder to push a couch than to push a chair? Open ages 8–11How does a glass screen know exactly where your finger is? Open
After you watchWhy does rubbing a balloon on your hair make it stick to the wall?

The short answer

Rubbing a balloon on your hair scrapes tiny invisible electric charges onto it. Those extra charges pull on the wall, and that pull is what holds the balloon up — the balloon never actually becomes sticky like glue.

Try this next

  • What if you rub the balloon longer, or hardly rub it at all? In the experiment, predict whether more rubbing means a stronger pull, then load it up and see how the stickiness changes.
  • What if the wall is damp instead of dry? Predict first, then think about the humid-day case in the explainer: does the balloon hold its charge as long when the air is wet?
  • What if you touch the charged balloon to a metal pole before putting it on the wall? Predict whether it will still stick, then drain it on the pole in the experiment and watch what happens to the pull.
The whole story

How it works

Everything is made of tiny bits, and some carry an electric charge. When you rub a balloon on your hair, it picks up extra negative charges (electrons) from your hair. When you hold the charged balloon near a wall, its charges tug on the charges inside the wall: the opposite charges in the wall shift a little closer and the matching ones move away, so the balloon and wall pull toward each other. That electric pull is strong enough to hold the balloon against gravity. Touch the balloon to a metal pole and the extra charges flow away, so there is nothing left to pull, and the balloon falls.

What people get wrong

People often think the rubbing makes the balloon physically sticky or warm, like glue or tape. It does not. The balloon's surface is exactly the same as before; only the invisible charge has changed. The proof is that draining the charge (by touching metal) makes the 'stickiness' disappear instantly, even though the balloon hasn't changed shape, texture, or temperature in any way you can feel.

The catch

A charged balloon sticks well, but not forever: the charge slowly leaks into the air, faster on a humid or rainy day, so the balloon eventually drops on its own. You can prove the stickiness is really charge by draining it on a metal pole, but then you have an empty balloon and have to rub it all over again to make it stick.

Questions kids ask

Does rubbing make the balloon sticky like glue?

No. The balloon's surface stays exactly the same. Rubbing just moves invisible electric charges onto it, and those charges pull on the wall. Drain the charges off and the balloon falls, even though nothing about its surface changed.

Why does the balloon eventually fall off the wall by itself?

The extra charges slowly leak off the balloon into the surrounding air. Once enough charge is gone, the pull on the wall is too weak to beat gravity, so the balloon drops. This happens faster on damp, humid days because moist air carries charge away more quickly.

Why does it work better in winter or on dry days?

Dry air lets the balloon hold its charge for longer, so the pull stays strong. On humid days the water in the air drains the charge away quickly, which is why static tricks often fizzle in summer or rainy weather.

How can a charged balloon stick to a wall that isn't charged?

The wall doesn't need its own extra charge. The balloon's charges nudge the charges inside the wall, pulling the opposite ones a little closer and pushing the matching ones away. Since the attracting charges end up nearer, the balloon and wall pull together.

Talk about it

  • Guess first: when the balloon sticks, do you think the wall is doing anything, or only the balloon?
  • Why do you think this trick works so much better on a dry winter day than a rainy one?
  • If the balloon never gets sticky like glue, what do you think is actually holding it up there?

For 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 toward the balloon and pushing negative charge away. Because the attracting charge is now slightly nearer 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 in humid conditions) or to a conductor such as a grounded metal pole.