Geo World Resources

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Introduction

Tired of walking?  Bored with sitting around?  Try hovering! Read the explanation and follow the links below to find out how this works.

Collect the materials and follow the instructions to construct your very own super-fast hovercraft!
 

    Safety Information
Experiments are dangerous, but scientists are always safe!

Always have an adult help you collect the materials and conduct the experiment.
Be careful when you're getting ready to ride the hovercraft.  You'll need one person to hold the craft and help push it. We recommend you sit on the hovercraft before you put inflate the plastic sheet with the leafblower.  You may also want to add a handle to the hovercraft to help you stay on. 
This experiment should be performed in a large space, as the hovercraft can move quickly. 
You should wear a helmet when you're riding the hovercraft, just in case!

 

 

 

 

 

 

Materials
Plywood circle 4 ft. diameter,  3/8-1/2 in. thick
Heavy plastic sheet, 5 ft x 5 ft
Leaf Blower
Drill
Small plastic disk, like a coffee can lid.
Staple gun
2 in. Bolt
Nut
2 fender washers
smooth floor
Instructions
1)


2)


3)

Drill a 5/16 inch hole in the exact center of the plywood circle; the 2 inch bolt should pass through it easily.
 

Cut a hole halfway between the center and the edge of the plywood circle.  Draw the hole first by tracing the mouth of the leafblower.

 

Lay the plywood disk on the large plastic sheet, fold the sheet over the plywood and staple the sheet to the plywood about every 4 inches using the staple gun. The plastic sheet should be tight but not too tight.  Cut off the excess plastic and tape the edges down. (picture)

 
 
4) Poke a hole in the center of the plastic disk. Attach it to the bottom of the hovercraft, over the plastic sheet, lining up the holes.  Secure it in place by putting the fender washers on either side of the plywood and then the nut and the bolt on either side of the fenders.
5) Cut six 2-inch vent holes in the plastic around the center of the plywood, within a few inches ofthe plastic disk.

 

 
6) Flip the hovercraft over so the plastic sheet is on the bottom, set it on the floor, stick the leaf blower into the hole and turn it on.  The plastic will inflate.

    

Vrooooooooooooooooooooooooom!

 
Explanation
  What would happen if you sat on your plywood circle without the plastic underneath?  Probably nothing. This is because of friction.
  When two dry objects move past one enough there is a force on them called static or sliding friction. This friction slows the objects down.  Imagine you are sitting on a regular playground slide. You slide down it. Fun, right? Now imagine you're on a water slide.  Why can you go faster on a water slide? (picture)

On a water slide, the friction is called "fluid" friction, or drag.  Now, instead of having your body rub against the slide, there is a layer of water in between you and the slide.  This water makes it easier to move quickly.

When there is just air between two objects, there is even less drag and more speed. Have you  ever seen an air hockey table?  In air hockey, the hockey puck floats on air that is blowing on the surface of the table.  This is what makes it move so fast across the table. In this experiment, the hovercraft is just like the hockey puck. The vents in the plastic sheet allow air to escape from the bottom, just enough to create a thin layer of air.  This reduces the drag and lets your hovercraft really fly!
 
 
Links
Friction

A student report gives a basic definition of friction

The Science of Hockey

Explains how ice reduces friction

Hovercraft: Traveling the Final Frontier

A student's project describes how the hovercraft may be used for exploration of Mars

The Physics of Skiing

Explains how gravity, inertia, mass, and friction make skiing possible

 

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