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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!
Experiments are dangerous, but scientists are always safe!
have an adult help you collect the materials and conduct the experiment.
|→||Plywood circle 4 ft. diameter, 3/8-1/2 in. thick|
|→||Heavy plastic sheet, 5 ft x 5 ft|
|→||Small plastic disk, like a coffee can lid.|
|→||2 in. Bolt|
|→||2 fender washers|
Drill a 5/16 inch hole in the exact
center of the plywood circle; the 2 inch bolt should pass through it
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.|
Cut six 2-inch vent holes in the
plastic around the center of the plywood, within a few inches
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.
|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!
A student report gives a basic definition of frictionThe Science of Hockey
Explains how ice reduces frictionHovercraft: Traveling the Final Frontier
A student's project describes how the hovercraft may be used for exploration of MarsThe Physics of Skiing
Explains how gravity, inertia, mass, and friction make skiing possible
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