Rocket Powered Skateboard

Use a Mentos and Diet Coke Geyser to transform a skateboard into a rocket

Anyone who has tried the Mentos and Diet Coke Geyser will tell you that it is totally awesome! But how awesome would it be if you turned that geyser horizontal, strapped it to a skateboard, and made the whole thing an eruption-powered rocket car? You might not believe the amazing results.

Materials

2-liter bottle of diet soda
Roll of Mentos mints
Duct tape
Skateboard
Piece of paper
Cardboard
A helper
Safety glasses

Experiment
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Reviews

Find a safe and suitable launch site for your Rocket Powered Skateboard. Empty parking lots, park sidewalks, and driveways all work great.
Attach a full 2-liter bottle of diet soda to the skateboard so that the geyser will have a clear shot, backwards, off the skateboard.
Check out the shape of your skateboard. If the skateboard has curved ends, you may need to add some cardboard underneath the bottle so that the geyser will completely clear the skateboard. If the geyser hits the skateboard, you won't get much propulsion.
Once you have the bottle placed, use duct tape to hold it in place. If you need, ask a helper to hold it while you tape. Make sure that the bottle is lined up with the skateboard for optimum launch power.
Hold your rocket so that the soda cap is facing up.
Unwrap a whole roll of Mentos. Roll a piece of paper into a tube just big enough to hold the loose Mentos. You want to be able to position the tube directly over the mouth of the bottle so that all of the candies drop into the bottle at the same time.
There's only a split second to set the system on the ground before a cascade of erupting soda comes gushing out at you. Once the Mentos drop, put the rocket down as fast as you can and get out of the way!

...there it goes!

Try This!

Try these variables to build the fastest rocket powered skateboard:

Use different types of soda.
Use different amounts of Mentos.
Try other candies.

Try these variables to build the fastest rocket powered skateboard:

Use different types of soda.

Use different amounts of Mentos.

Try other candies.

How does it work?

Soda basically consists of lots of sugar, some flavoring, water, and preservatives. What gives soda its bubbly appeal is invisible carbon dioxide gas that has been forced into the liquid using tons of pressure. Until you open a soda, which makes room in the soda bottle, the gas mostly stays suspended in the liquid and can't collect to form bubbles, which is what gases naturally do. However, if you shake the soda and then open it, he gas is quickly released from the protective hold of the water molecules and escapes with a whoosh, taking some of the liquid along with it.

There are other ways to cause the gas to escape. Just drop something into a glass of soda and notice how bubbles immediately form on the surface of the object. For example, adding salt to soda causes it to foam up because thousands of little bubbles form on the surface of each grain of salt. Also, compare the foaming of diet soda to regular soda when each is poured over ice. The same happens when you drop Mentos candies into a soda! Each Mentos candy has tiny pits on its surface where bubbles form called nucleation sites. They're the perfect geyser starter!

The geyser is cool and everything, but how does it move the skateboard? Well, Newton's Third Law of Motion states that for every action there is an equal and opposite reaction. The foresee of the soda geyser whooshing backward out the bottle is exactly matched by a force pushing the rocket forward. The strong the backward geyser, the faster the car moves forward. That's why you tested different sodas and amounts of Mentos, to get the best launch!

Harder than it looks

Richard Uchytil - June 6, 2012

This user gave 3/5 stars

I couldn't get the Mentos in the bottle fast enough to make this work, it just sprayed all over myself and when I finally put it down most was gone so it didn't go anywhere. I tried it a 2nd time, a little better but still had problems. Looks like fun, I probably just need to practice more.