Why Do Our Ears Pop on an Airplane?

Jeff from State College, PA, is going to Florida for his Spring Break and will be taking an airplane to get there so he asks, why do our ears pop when we fly?

The human ear consists of the outer ear, middle ear, and inner ear which is fairly deep inside of your head. The middle ear is separated from the outer ear by the eardrum allowing the air trapped inside the middle ear not to come in contact with the air outside of your head. When you experience a change in air pressure by getting closer to or further from the ground, your ears will occasionally "pop" to adjust the pressure of the air that is caught in your middle ear so that it matches the air pressure outside of your head. This is done by quickly opening the Eustachian tubes, which connect the middle ear to the back of the nose, in order to let air rush in or out of the middle ear as needed.

The most common place for someone's ears to "pop" is on an airplane, but it can also happen with smaller changes in altitude (the height above the Earth's surface), like when you are driving up or down a mountain. The air closer to sea level is at a higher pressure since it is being compressed by the weight of all of the air above it. As you climb to higher and higher altitudes, the air pressure decreases. Some people may find the popping of their ears to be annoying, but if your body didn't do this, then the pressure on one side of the eardrum would be higher than on the other side which could bend your eardrum slightly and compromise your hearing.

If your plane is taking off, then you are going to an area with lower pressure so the high-pressure air in your middle ear will push outwards on the eardrum. When your ears pop, air rushes out. If you are coming in for a landing, then you have low-pressure air in your head (from when you were at a high altitude) and high-pressure air outside pushing inwards on your eardrum. When your ears pop, air rushes in.

One way to make this pressure equalization more comfortable is to do it yourself by swallowing or yawning frequently rather than waiting for your ears to pop by themselves. These methods work because swallowing and yawning cause the Eustachian tubes to open briefly. This is why many people choose to chew gum when their plane is taking off or landing (chewing gum or sucking on a hard candy makes you swallow more than if your mouth were empty).

Little Lion Experiment:

If someone has a blocked or oddly-shaped Eustachian tube, then their ear will fail to pop as their plane is landing. This creates a small vacuum in the middle ear. Fluid then rushes into the middle ear to increase the outward pressure until it equals the inward pressure from the surrounding high-pressure air. This experiment will help you observe the effects of having a blocked Eustachian tube. You will need: a small plastic cup (if possible, use a clear cup), a bowl with a flat bottom, and some water.

Steps

1. Fill the bowl with about an inch of water.
2. Turn the empty plastic cup upside-down and squeeze it until it bends inward.
3. Place the bent cup in the water.
4. Being careful not to let the lip of the cup rise above the water level, slowly squeeze the creases in the cup outwards so that the cup returns to its original shape.

By doing this, you are creating a small vacuum. So, the pressure inside the cup (which pushes outwards) is lower than the pressure outside of the cup (which pushes inwards), and this pressure difference is what pushes the water from the bowl into the cup until the two pressures are equalized. As a side note, the same principles of air pressure explain how straws, turkey basters and a variety of other objects are able to move liquids against gravity.

Why Do Your Ears Pop On An Airplane?

The human ear consists of the outer ear, your middle ear, and your inner ear which is fairly deep inside of your head. The middle ear is separated from the outer ear by the eardrum (or "tympanic membrane" in medical terms). So, the air trapped inside the middle ear doesn't come in contact with the air outside of your head. When you experience a change in air pressure by getting closer to or further from the ground, your ears will occasionally "pop" to adjust the pressure of the air that is caught in your middle ear so that it matches the air pressure outside of your head. This is done by quickly opening the Eustachian tubes (which connect the middle ear to the back of the nose) in order to let air rush in or out of the middle ear as needed.

The most common place for someone's ears to "pop" is on an airplane, but it can also happen with smaller changes in altitude (the height above the Earth's surface), like when you are driving up or down a mountain. The air closer to sea level is at a higher pressure since it is being compressed by the weight of all of the air above it. As you climb to higher and higher altitudes, the air pressure decreases.

Some people may find the popping of their ears to be annoying, but if your body didn't do this, then the pressure on one side of the eardrum would be higher than on the other side which could bend your eardrum slightly and compromise your hearing.

If your plane is taking off, then you are going to an area with lower pressure so the high-pressure air in your middle ear will push outwards on the eardrum. When your ears pop, air rushes out. If you are coming in for a landing, then you have low-pressure air in your head (from when you were at a high altitude) and high-pressure air outside pushing inwards on your eardrum. When your ears pop, air rushes in.

One way to make this pressure equalization more comfortable is to do it yourself by swallowing or yawning frequently rather than waiting for your ears to pop by themselves. These methods work because swallowing and yawning cause the Eustachian tubes to open briefly. This is why many people choose to chew gum when their plane is taking off or landing (chewing gum or sucking on a hard candy makes you swallow more than if your mouth were empty).

If someone has a blocked or oddly-shaped Eustachian tube, then their ear will fail to pop as their plane is landing. This creates a small vacuum in the middle ear. Fluid then rushes into the middle ear to increase the outward pressure until it equals the inward pressure from the surrounding high-pressure air.

Little Lion Experiment:

To see the effects of having a blocked Eustachian tube, obtain a small plastic cup and a bowl with a flat bottom. If possible, use a clear cup so the water will be easier to see. If you don't have a clear cup, then try adding food dye to the water in this experiment to it will be easier to see once it is inside of the cup. Fill the bowl with about an inch of water. Turn the empty plastic cup upside-down and squeeze it until it bends inwards. Place the bent cup in the water.

Being careful not to let the lip of the cup rise above the water level, slowly squeeze the creases in the cup outwards so that the cup returns to its original shape. By doing this, you are creating a small vacuum. So, the pressure inside the cup (which pushes outwards) is lower than the pressure outside of the cup (which pushes inwards), and this pressure difference is what pushes the water from the bowl into the cup until the two pressures are equalized.

As a side note, the same principles of air pressure explain how straws, turkey basters and a variety of other objects are able to move liquids against gravity.

How Do Airplanes Stay in the Air?

Flying for the holidays? Or, did grandma fly in to visit you for Christmas? Have you ever wondered--while on a plane or watching one--how a heavy, metal plane flies through the air?

Whether you are scared of flying or not, the answer to this question is a little frightening. Physicists and aeronautical engineers continue to debate the basic mechanics of flight. This is even more suprising when you consider that the Wright brothers invented the plane over 100 years ago! In spite of the debate, everyone agrees that flight boils down to physics. Yes, this means that no invisible strings are hanging from space!

Most will go on to explain that a plane's ability to fly results from air traveling faster over the more curvaceous top surface of the wing than under the flatter bottom surface. The quicker a fluid like air moves, the less pressure it exerts. This phenomenon is known as Bernoulli's principle and was discovered by Daniel Bernoulli, an 18th century Swiss mathematician. The principle helps us to understand how slower moving air below the wing exerts more pressure on the wing than the faster moving air above it. This results in an upward force called lift. Lift pushes the aircraft upward against the downward pull of gravity.

This principle is well-accepted and accurate, but it does not help us to understand why the air flowing over the wing moves faster. This lack of explanation causes confusion among physicists and aeronautical engineers. One of the leaders in helping to explain this phenomenon, Jef Raskin, actually started his research by arguing with one of his middle school teachers. He argued that this principle didn't make sense because he had seen planes fly upside down. Raskin felt that Sir Isaac Newton's laws of motion were a better explanation, as "a wing is just a device for forcing air down." According to Newton's third law, for every action there is an equal and opposite reaction, so the downward force that the wing applies to the air produces an upward force of the air on the wing. The amount of air directed downward depends on the angle of the wing (the angle of attack) and not the shape of the wing. This would help explain why a plane can fly upside down.

Although Newton's law helps to explain how planes can fly upside down, most believe that both Bernoulli and Newton help to explain flight. They also recognize that curves on the top of the plane are important and without them an airplane may stall and fall.

Flight is a fascinating science, and many aspects of why we can fly are still under debate. Start asking your teacher questions and maybe you will help get some of the debate of flight mechanics off the ground!

Source: Chang K. "What Does Keep Them Up There?" New York Times. 9 December 2003.

Little Lion Experiment

An important concept in understanding how objects move is gravity. Gravity is the tendency of matter toward some attracting body, particularly towards the center of the earth. To understand the effect of gravity or a flying objects attraction to the ground, drop varies objects such as a piece of paper, a shoe, a book, and a feather from a table. Guess, watch, time, and test which object falls the fastest.

Gravity adds weight or force - an equal amount to each object. But, gravity increases the force or speed of motion on the heavier objects. Thus, the heavier objects such as a shoe or book would beat a piece of paper or feather. You can also feel this principle at work when you slip on ice with and without your book bag! Be careful this winter!