Air Pressure

Our topic this month was air pressure. We talked about how air is constantly pushing down on us and everything around us and the only time we can actually see or feel air pressure is when there is a sudden change in air pressure, like ears poping on an airplane.

We used a simple experiment that can be done with all your left over Easter eggs! 

Egg in a Jar:

  • Glass bottle or jar with the opening slightly bigger than the egg.
  • Peeled hardboiled egg
  • Lighter or match
  • Paper

Although this is a simple experiment, it really shows how air pressure works on an object!

Light your piece of paper on fire and drop it into the glass bottle. I explained that we were using fire to remove the oxygen in the jar, (since fire eats oxygen). By removing the oxygen in the bottle we are causing the air pressure to become greater on the outside of the egg, I used the term “heavier air”.

Place your egg on the mouth of the bottle. It will vibrate as some of the hot air escapes. As the air becomes “heavier” or the air pressure increases on the outside of the egg it will slowly push the air into the bottle.

Here is a great video: 


Now that we have the egg in the bottle how do we get it out? Well, we apply the same concept. If we use “heavy air” to push our egg in the bottle we need to use “heavy air” to push it out.

Turn your bottle upside down so the smaller part of the egg it pointing outwards but not fully covering the opening. From here place your mouth on the opening and blow, hard! While you blow a continuous stream of air roll the egg over the opening, the pressure you created in the bottle should push the egg back out! The video below gives a great demonstration.

Inverted Glass & Card:

  • Water
  • Glass
  • Index card or playing card

I am sure we have all preformed this “experiment” before.

Fill your glass with water, place card over the top and invert. Because air exerts pressure equally from all directions the card does not fall due to this principle.

We listened to a song that reinforced the effects of air pressure. Just a warning, it’s slightly out of tune but very catchy!

  

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