View source for STAHP

{| class="wikitable" style="color:black; background-color:#ddd; margin-left: auto; float:right"
| [[Physics]], [[Engineering]]:
| Air Pressure, Hoverboards
|-
| Grade Range:
| [[Elementary School]], [[Middle School]], [[High School]]
|-
| Format:
| [[Hands-on]], [[Stage]]
|}

The '''''Science Theatre Air Hockey Puck'''''s, or '''STAHP'''s, are the two hoverboards that Science Theatre has. The hoverboards are fun for all grades, and function well as either a hands-on or stage demonstration.

== Materials ==

* A Hoverboard (We have two to choose from)
* Shop Vacuum with Hose

== Safety Precautions ==

Please read the Physical Demonstration section of the [[Demonstration Safety]] page before performing this demonstration.

This demonstration should only be performed on a solid, flat surface, such as a wood or tile floor. This demonstration won't work on uneven ground or on padded ground, such as carpet or grass.

== Demonstration ==
;Stage:
# Ask the audience if they have ever played air hockey. Ask those who raised their hands if any of them have noticed how the air hockey table works.
# Show the hoverboard, and explain that it is the '''''Science Theatre Air Hockey Puck''''', or '''STAHP'''. point out the membrane on the bottom with holes throughout it, which gives an effect similar to what you see with an air hockey table.
# Ask for a volunteer from the audience. Have them stand in the center of the hoverboard, holding the hose in the pvc pipe hole. Turn the blower on high, and watch as the board starts moving! If needed, help them orient themselves on top, and figure out how to steer on the board.
# Have the volunteer return to their seat, and hover on the hoverboard yourself!

;Hands-on:
# Set up the hoverboard, and ask students as they come up if they would like to try to ride it. If so, have them stand in the center of the board and hold the hose in the pvc pipe hole, and then turn the blower on high. Let each student hover on the board for 10 seconds or so before having the next student try to ride it.
# Be sure to give a brief explanation for the hoverboard to the students. If you have a line forming, you can give the whole line the explanation before having them take turns on it.

== Why This Works ==

Air hockey is a common arcade game, where you hit a plastic puck back and forth and try to score it in the opponent's goal. Air hockey tables make the puck hover above the tables surface by blowing a thin layer of air across the table surface, which the puck sits on top of. This is because of a difference in ''air pressure'', or a difference in how much force is applied by the still air above the puck and the moving air below it. In this scenario, the moving air below the puck is pushing on the bottom and the sides of it. This means that the moving air is applying a ''high'' amount of pressure. The air above the puck is still, so it is applying a ''low'' amount of pressure on it. this difference in pressure results in the puck being lifted up into the still air above, away from the high pressure air below it.

This is the same concept that we have happen with the hoverboard. the bottom of the hoverboard has a membrane with a lot of holes in it. This membrane makes sure that the air blown into the pvc pipe hole is partially trapped, so it has to go out through the holes in the membrane. As it goes out through those holes, the air pushes against the floor and spreads out, which means that it is applying ''high'' pressure below the board. Since the air above the board is still, the board will try to lift into the ''low'' pressure above it, even if someone is standing on it!

== Additional Information ==

* This demonstration pairs well with the [[Bernoullis Principle]], as they show opposite effects happening which what initially looks like similar scenarios.
* This demonstration is a part of the [[Pressure Show]]