AN ANTIGRAVITY CHAMBER 1997 William J. Beaty Here's a quick way to generate "zero gravity." Actually, this really is a method for generating freefall weightlessness. The space shuttle orbits at about 300 miles above the earth. Did you know that at 300 miles above the earth, the gravity is only about 15% less than gravity at the surface? Gravity inside the space shuttle only APPEARS to be zero because the space shuttle is falling, and the astronauts are falling as well. Whenever any container is falling free, the contents of the container will APPEAR to be weightless. Of course the shuttle and its contents are moving sideways as they fall, so that they never hit the earth. Our "zero gravity generator" is simply a camera in a box. By shifting our point of view to the inside of a movable box, we can create genuine free fall, exactly the same as within any orbiting space craft. MATERIALS: - Camcorder or small TV camera - Television monitor - Long narrow cardboard box - Light fixture and floodlight - wooden boards TOP VIEW: _____ spotlight | ___|/| _________________________________ | <___ | . | ____|_____|\|_____________________ | | ______ . | | TOP | | |__- . | | VIEW | | |__ . | | | |______| - . | | |__________________________________| | TV camera on a board . | _________________________________| Cardboard Box CONSTRUCTION Cut the cardboard box so that one side is missing, which gives a good view into the long narrow box. Attach the board to the side of the box, and attach the camera to the board. (For convienence, use duct tape at first, screws and bolts later on.) Affix a small flood light adjacent to the camera, and aim it into the box so that the camera can "see." Connect power to the camera and flood light, and connect the camera to the TV or video monitor so that your audience can see into the box. Adjust the camera's zoom and focus to give the proper view of the interior (you may have to use "macro" mode.) For best depth of focus, make sure the interior of the box is brightly lit, then adjust the camera f-stop for a high number. OPERATION Place some objects inside the box. I just grabbed a spool of tape, some magic marker caps, and a bottle of white-out, and dropped them in there. Watch the image on the TV screen, and carefully rotate the entire box assembly until it is upside-down. Your audience will probably break out in laughter, because the box will remain still, but the objects in the box will crawl up the wall and roll around on the ceiling! Violently shake the box, and the objects will seem to be controlled by invisible forces. To generate free-fall, suddenly lift/jerk the box so that the objects are launched off the "floor" of the box, then try to move the box to follow the objects so they momentarily stay centered in the middle of the box. Don't let the box go, or you might damage your camera! Your audience will see genuine ( and very brief ) free fall effects. The objects will leap into the air, then will drift around spinning, then will suddenly fall hard onto the floor. FANCY VERSION If you have some ambition, you might wish to decorate the inside of your box. Paint it and add extra shapes to convert it into the inside of a space station. Add some small human figures (Barbie, etc.) dressed appropriately. Or, maybe decorate the interior so it looks like the padded cylindrical interior of NASA's "vomit comet" free-fall airplane. Dress your action figures in orange jumpsuits, and provide some air-sickness bags for the Senator! If you have a sick sense of humor, build the inside of a commercial airliner into your box. Add passengers and steward/stewardesses, luggage racks, etc., then simulate what would happen if the 747 pilots decided to do loop-the-loops! Fear of flying? Or, you can fill your box with doll-house furniture, then show what a moving van looks like as it bounces and rolls down a steep hill. An "adventure in moving!" This box/camera device duplicates the workings of NASA's free-fall simulator plane. Rather than climbing into a full sized aircraft, we use the video camera to shrink ourselves down and take a Virtual Reality ride inside the box. To generate free fall, the NASA plane flys in a parabola-shaped trajectory. Why? Well, imagine what would happen if the crew was inside of a box which was shot out of a huge cannon. Both the people and the box would fly along similar paths. The box would take a long, curved, up and down path, and so would the people inside. The people inside could not see the box move, so they couldn't know they were falling, instead would think that they were weightless (at least until the box struck the ground.) So, if an airplane flys in exactly the same path as a fired cannonball, everyone in the plane will seem to be floating. NASA free-fall aircraft: http://zeta.lerc.nasa.gov/new/Frame1.html SIMPLE NON-VIDEO VERSION If you find a small box like a shoe box or large cereal box, open one end, and stick your face in, you will have the "poor man's version" of the video camera box. Stick some small toys or coins into the box. To generate momentary free fall, simply jump up and down. The objects inside the box will float for a moment. ( Be aware that jumping up and down with a box on your face looks really stupid. This demo is a great excuse to convince OTHER people to jump around with boxes on their faces, while you stand back and watch!) WARNING Of course, always try to protect your camera. If you never let the box out of your control, then you'll only have yourself to blame for any mishap. Perhaps it would be wise to attach a hook to the ceiling, and attach the camera box to a rope to prevent accidental contact with the floor. A suggestion: use the tiny $80 video cameras sold by Herbach and Rademan, or by Marlin P. Jones. These things are a couple inches square, and can take lots more punishment than a camcorder. And if you drop it and break it, it was an $80 camera, not a $1200 camcorder. ((((((((((((((((((((( ( ( ( ( (O) ) ) ) ) ))))))))))))))))))))) William J. Beaty SCIENCE HOBBYIST website billbeskimo.com amasci.com EE/programmer/sci-exhibits science projects, tesla, weird science Seattle, WA 206-781-3320 freenrg-L taoshum-L vortex-L webhead-L