01/10/2024
WHY DO MY EARS 'POP' ON PLANES?
Have you ever taken a packet of crisps and a bottle of water on board an aircraft? If so, you may have seen some of the effects that also happen inside your ear.
If you take a packet of crisps on board and you don’t open the bag, take a look at what happens once you reach altitude. The packet swells up like a balloon. If you open the packet, you’ll notice a rush of air escaping from the bag.
This is all down to the difference in air pressure from the ground to the sky. Air molecules are more dense on the ground, as we get higher, the molecules move further apart. So this causes the air inside your sealed plastic bag to expand, pushing outwards on the packet. As soon as we open the packet, the air that was pushing outwards bursts out of the bag.
A similar thing happens inside your ears. Behind your eardrum is the middle ear, which acts very much like this packet of crisps. It’s an air-filled cavity that’s sealed so air can’t escape. As we take off, the difference in air pressure causes the air in our middle ear cavity to expand. This pushes outwards on our eardrum causing the eardrum to stiffen. This means it can’t vibrate in response to sound and everything sounds ‘dull.’
So how do we open our biological packet of crisps to relieve the pressure so we can hear normally again?
There is a very narrow tube (Eustachian tube) that links the middle ear space to our airways (to the back of the nose and throat). This tube is permanently closed. The only time it opens is when we yawn, swallow or if we force it open by performing a valsalva manoeuvre (trying to exhale while closing our mouth and holding our nose closed - see accompanying image).
Once this tube is open, the air that was pushing outwards is allowed to rush out, which allows our eardrum to return to it’s usual position where it is free to vibrate once more and our hearing returns back to how it should be. We get the sensation that our ear has ‘popped.’
So what about this water bottle?
Have a drink while in the air, screw the lid back on and watch what happens as the plane comes in to land. The bottle appears to ‘cave in.’
This is once again due to the air pressure differences at different altitudes.
When you’re in the air, and you’ve sealed the bottle, as you descend, the reverse to the crisp packet scenario occurs. This time, the air molecules that were far apart when in the air, start to come closer together as the plane descends. In other words, the air ‘shrinks.’ This has a kind of vacuum effect and it pulls the walls of the bottle inwards.
The same thing is mirrored in our ears. Instead of the air pressing outwards and causing our eardrum to bulge, this time our eardrum is 'sucked' inwards. This stiffens the drum and causes it to become less mobile so it cannot pass on sound waves. Everything sounds 'dull.'
This process can actually be quite painful. This is why you always hear babies and children crying on landing. Their ears are hurting and either they haven’t yet learnt how to open their Eustachian tube by yawning/swallowing, or their Eustachian tube is so small and floppy that it won't open and the air cannot rush in to equalise the pressure and allow their eardrums to return to a normal position.
Other factors can be at play with children’s ears too which causes a more painful experience… But that’s for another blog post.
And if you’re unfortunate in that you experience issues like this as an adult, there are multiple reasons why this may be happening to you and there are several things you can try that might help. I’ll write another blog post about this soon.
