Egg Drop - Newton’s Law of Inertia
The Egg Drop is a classic science demonstration that illustrates Newton's Laws of Motion, namely inertia. The challenge sounds so simple... just get the egg into the glass of water, but there are a few obstacles. The egg is perched high above the water on a cardboard tube, and a pie plate sits between the tube and the water. Still think it's easy? Sir Isaac Newton does.
- Cardboard tube
- Pie pan
- A large drinking glass
- Tray (optional)
- Coloring Tablets (optional)
Warning: Always wash your hands well with soap and water after handling raw eggs. Some raw eggs contain salmonella bacteria that can make you really sick!
- Fill the large drinking glass about three-quarters full with water.
- Center a pie pan on top of the glass.
- Place the cardboard tube on the pie plate, positioning it directly over the water.
- Carefully set the egg on top of the cardboard tube.
- With your writing hand, smack the edge of the pie pan horizontally. Don't swing up, and don't swing down! It’s important that you hit the pie pan horizontally and use a pretty solid hit, so plan on chasing the plate and tube.
- Your astonished guests will watch the egg plop nicely into the water. It’s even more fun to watch someone else try to drop the egg. Science is so cool!
Take It Further!
- Try setting up a tray (like one that you would get from a fast food restaurant) on top of five glasses. USe five tubes and five eggs and see if you are an egg drop master! *HINT* The angle that you hit the tray from can make all the difference.
- Add coloring to the water in your egg drop for added effect.
- Try testing longer tubes, more or less water, different liquids in the glass, different water containers, and heavier or lighter falling objects.
How Does It Work?
Credit for this one has to go to Sir Isaac Newton and his First Law of Motion. He said that since the egg is not moving while it sits on top of the tube, that’s what it wants to do - not move. You applied enough force to the pie pan to cause it to zip out from under the cardboard tube (there’s not much friction against the drinking glass). The edge of the pie pan hooked the bottom of the tube, which then sailed off with the pan. Basically, you knocked the support out from under the egg. For a brief nanosecond or two, the egg didn’t move because it was already stationary (not moving). But then, as usual, the force of gravity took over and pulled the egg straight down toward the center of the Earth.
Also, according to Mr. Newton’s First Law, once the egg was moving, it didn’t want to stop. The container of water interrupted the egg’s fall, providing a safe place for the egg to stop moving so you could recover it unbroken. The gravity-pushed egg caused the water to splash out. Did someone get wet?
- Rotational Motion Review by CJP
It's important to note that it is not only inertia that keeps the egg from flying away like the pan and the tube did. You only hit the pan- so why did the tube go flying? Because the edge of the pan hit it. So why didn't the tube then hit the egg and send it flying in the same direction as the pan and tube? The tube is hit on the lower edge, so it rotates (rotational motion) as it is flying away (translational motion). This rotational motion causes it to roll out from under the egg which then allows gravity to take over and drop the egg straight down into the water.
(Posted on September 29, 2012)
- Great experiment!! Review by cathy
My second grade son had to do a "how to" presentation and we decided on this experiment. His presentation for the whole class was flawless. He then asked for a volunteer from the class to try the experiment...went flawless again. Then he had the teacher try! She wasn't listening to well to the directions given by her student, my son, and she smacked the pie plate and the glass over in one big swoop of her arm sending the egg and water flying!! It was hilarious. After a few more attempts she finally got it. I guess she needs a few tips on listening:)
(Posted on May 8, 2011)
- the egg drop Review by jennifer
I have to say that egg drop trick was so cool i had to use 3 eggs because my famialy was real nevous and tjey didnt have faith in thereselfs.thank you for showing that experiment.Also I did thta experiment in science class yesturday when my teacher said to go on this website.Well also we have a science fair project due the week before christmeas.First i was going to do electricity but now im not.Thank you very much.
(Posted on November 21, 2009)
- DIY science experiment Review by Kevin
I took more than 3 hours trying to find a good DIY experiment on the web. This was the only one I could find that fulfilled and even exceeded my expectations.
I guarantee it to be a good experiment to do.
(Posted on November 7, 2010)
- Preschool Egg Drop Review by Miss Donna
This demonstration was a huge hit with my 4 year-old group!
We found that a plastic Easter egg with a few pennies inside (4 or 5) made a great "pratice egg." With a no mess egg alternative, I was able to let each child take a whack or two at the pie pan! (ducking the flying pan became another favorite part of this activity) Thanks!
(Posted on March 16, 2011)