Why do balloons go bang when they’re popped?

Monday 1st August 2011
Submitted by mstaple
MARCUS ROWLAND, MASSACHUSETTS

The air in a balloon is at a higher pressure than its surroundings because the elastic tension of the balloon skin is pulling inwards. When you stick a pin in the side it creates a tiny hole. The rubber around the edge of the hole isn’t being pulled uniformly in all directions any more because there isn’t any force exerted from the centre of the hole. So the net force pulls the rubber away from the hole, which makes it bigger and the force imbalance increases. In a fraction of a second, the entire skin of the balloon has contracted all the way back to a point on the opposite side from the pin. The high-pressure air that was inside the balloon is now free to expand and this creates a pressure wave that our ears hear as a bang. If you put a piece of sticky tape on the balloon first and then push the pin through that, the balloon doesn’t go bang. That’s because the sticky tape isn’t under tension and it is strong enough to resist the force from the rubber as it tries to pull back. So the pinhole remains small and the air just leaks out slowly. Likewise, the silvery, Mylar balloons that usually contain helium don’t pop very well because Mylar is a pre-stretched plastic and so it isn’t very elastic.

GOT A QUESTION?

Scratching your head over a burning scientific conundrum? Submit your question and we'll get our esteemed panel of experts to answer it for you.

 

Can you get sunburnt underwater?
previous qanda Article
Do viruses die?
next qanda Article
Q&A Tabs

Ordinary soap and water washes your hands by removing surface dirt, oil and loose skin. Studies have shown that washing your hands and drying them on a paper towel reduces the bacterial count by...

When experiencing a bad headache or other acute pain, most people reach for tablets of the ‘big three’ over-the-counter painkillers: aspirin, paracetamol or ibuprofen. But which one...

A lunar month is slightly shorter than a calendar month, so every two to three years, there is an extra lunar cycle above the usual 12. This additional moon is called the ‘blue moon’...

Down on Earth, when we blow air into a mixture of soapy water, a bubble forms as the growing ‘bag’ of air formed from the soap film moves the surrounding air out of the way. In the...

Motion sickness in general is caused by a conflict between visual information and the organs of balance, and occurs to a greater or lesser degree in all the higher vertebrates. Some animals,...

All female mammals have a clitoris, the sole purpose of which is to react to sexual stimulation, and presumably this stimulation has evolved to be pleasurable for most species. But establishing...

To create a sound, we have to set matter - whether it's a gas like air, a liquid or even a solid material - in regular motion, creating a wave of specific frequencies, which we hear as a sound of...

Mirrors don’t reverse left and right either – that’s just our interpretation of what happens. Your reflection in the mirror is actually reversed front to back – if you have...

Discovered by an American student named Gary Flandro in the mid-1960s, the slingshot manoeuvre usually involves spacecraft briefly 'coat-tailing' a planet orbiting the Sun, extracting some of the...

The ice disappears because the wind blows away water molecules that have evaporated or 'sublimed' from the ice, so the ice slowly shrinks in size. The molecules that escape are those with the...

We use cookies to improve your experience of our website. Cookies perform functions like recognising you each time you visit and delivering advertising messages that are relevant to you. Read more here