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Inertia & Gravity

Science Lab

How does it work?






The Experiment

Each group had a plastic cup, a note card, and a coin.


The placed the note card on top of the cup, and the quarter in the center of the note card. 


When we quickly removed the card, what do you think happened?


The quarter fell straight down into the cup!








Videos of the Experiment

Be patient…the videos take a minute to load!


Click here to see Juan & Vinci successfully complete the coin “trick”.



Click here to hear Tori & Savannah explain how the “trick” works.





How it works

We learned about gravity and inertia.  Gravity is a force that pulls everything towards the center of the earth.  Inertia is a law of motion that says that an object will stay at rest unless a force acts on it that is strong enough to move it.


When doing the quarter “trick”, a force is applied the note card.  Because the note card is smooth, no force is applied to the quarter so it stays in place.  Then, gravity pulls it into the cup.



This is the same way that magicians pull tablecloths out from dishes and glasses without breaking them! 


Click here to see a video clip of scientist Robert Krampf explain more about inertia, while doing the tablecloth trick.



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