How can you easily make a projectile Launcher?
923092
PVC pipe 6 inch reducer down to 2 inch bout 2 foot of 6 inch 3 foot of 2 inch hole in the top of 6 inch with plug in other end shove potatoe in the end of 2 inch spray starting fluid in hole on top of 6 inch and light her up.
1116467
I am not sure how cheap you are looking for, but here is s start.\n\nhttp://www.hobbytron.com/RobotArmKits.html
568149
pfft the best weapon to use would obviously be a Rocket Launcher that shoots chainsaws that are uhhh... on fire ohhhh and it homes in on you and.... it turns into a shark and eats you while the chainsaw cuts and burns you then it pours alcohal on you sooo you would be like OWWWWWWWWWWWWWWWWWW! then it drops a really heavy weight on you that .... EXPLODES!
731455
Something that may be fun is a project with model rockets. Give them the necessary information to calculate the height of the rocket, based on the rocket engine and mass of the rocket as homework.\n\nThen at school, fire a few of them and using basic trig calculate the height and see how close they are.\n\nRocket engines are typically rate something like: A8-3 which breaks down as follows:\nA --> 2.50 Newton-seconds of power\n8 --> average thrust (in newtons)\n3 --> seconds from end of thrust to ejection charge (parachute)\n\nThe engines also have a time-thrust curve that shows how the power is delivered over time. Check the following link below for some more info:\n\n------------------------------------------------------------------------\n\nHere is another one:\nNot sure how readily available props are for you but if you can hook up a camera in a room with a strobe light/flash and then set up a collision (air hockey table or pool table come to mind) then you can calculate the velocity of each object, measure its mass and then demonstrate the conservation of momentum using vectors. Because you know the frequency of the strobe, and the distance traveled, you can compute the vector velocity.\n\nOr how about:\nFirst, fire an arrow down a football field. Given the amount of time aloft calculate the initial velocity (ignore air resistance/friction) Then fire an arrow at a bale of hay (extend the bow by the same amount) and measure how far into the bale the arrow went. Using the same initial velocity and distance into bale, calculate the rate of deceleration and coefficient of friction of the hay bale.
450194
Take 3" dia pvc and cut to 18" length. Add screw cap to one end and 1 1/2" x 30" pvc pipe to other end. Get gas grill push button lighter (Wal-Mart/Lowes/Home Depot) and drill hole in 3" pvc about 4" from screw cap and the same circumference as lighter body. Apply some pvc pipe glue around drilled hole and insert lighter. Allow to dry and then apply nut on underside of lighter body inside of pipe(nut supplied with lighter). Sharpen edge of 1 1/2" pipe end.Shove lemon or potato of larger diameter down pipe and tamp down about 18". Unscrew cap and spray hairspray into pipe. Re-cap and put on shoulder like bazooka or hold at side and push button. Can shoot well over 100ft. Pvc $5 Lighter $8 Glue $3 Hairspray $1.50 Lemons $2 Scaring the crap out of your neighbors...PRICELESS.
67074
You mean like a model rocket?\nTry Estes Industries at the site below.  They have been in the business for decades and have a wide variety of models from which to choose.  Check with your local laws first.  These are not legal everywhere.
767612
You will need to investigate the chemical mixture to use, there are common ones like black powder (Potasium Nitrate [saltpeter] + charcoal + sugar) I used to buy saltpeter at the drug store (in the olden days they gave it to boys to reduce sex cravings...) but I don't know if it is available there anymore...\n\nYou need 2 other components besides the fuel - 1. A nozzle, and 2. An igniter. \n\nThe simplest nozzle would be a straight hole drilled through a plug (that would close the bottom of your cylinder rocket body full of fuel). But a point to point cone shape would be better. Another alternative, I saw a design for a model rocket which used an empty CO2 cartridge (like a BB Gun would use) the cartridge end is very nozzle like and you just fill it with your fuel.\n\nFor the ignitor, there is something called nichrome wire, it is a thin wire that when you attach a battery to it, it gets hot (even easier though, they sell little ignitors at hobby stores for estes type model rockets.) You would have to mount the ignitor into your fuel and plug up any remaining space so that the fuel doesn't fall out...
849450
Try this...Take a square piece of paper and fold it into a triangle.  Now fold a series 1/4 folds (3 or 4) on the wide end.. then insert one end into the other (if it doesn't stay then use a small piece of tape to hold together)  What you will have is a cylinder type of craft.. to launch it hold it by the tail (the tip of the triangle) with your middle finger on the inside and all others on the outside... The position should be that the most paper should be facing down\n\nNow just flick you wrist and let go... if you did it correct you will have a futuristic paper air plane that will fly further than most conventional ones..
917846
Lots of variables here. Do you want one that will move with directional intent, or one that just floats?\n\nThe simplest method for making a "hovering" vehicle would be to take the vacuum engine, mount it onto a curved shield, with the curvature facing down. Make sure your shield is a very light material, balsa wood works, i suppose.\n\nIf you know where the vacuum's intake and output valves are, then it's easy. make sure you make a hole for the output, and secure the engine to the top of the shield. Turn on the engine, and watch the contraption float around aimlessly. It's basically how a air hockey table works, except in reverse.\n\nEDIT: one important detail. Are you trying to make a hover car strong enough to hold your weight? Because that would need one hell of an engine.
815673
OK I'm cheating - I put this answer up a little while ago.\n\nA quick and dirty idea for a physics project would be one based on electromagnetism. Without knowing what grade you're targeting, a simple one that has a fair amount of pizzazz is to build a gauss rifle. Checkout http://sci-toys.com/scitoys/scitoys/magnets/gauss.html\n\nThe sci-toys site has some other pretty cool stuff that you might find useful as well.\n\nFor a more advanced example, you can make a small rail gun that applies similar principles but can have a much larger kick. Just do a search on "rail gun experiment".\n\nEnjoy!!
827148
MacGyver would know for sure!  I'm thinking you can make a slingshot with those items.
11475
Well it is pretty easy to build a simple motor. There are instructions at this website.
317575
This is actually pretty easy.\n1) Take a 2 liter bottle and poke a hole in the cap (with a sharp knife or philips head screwdriver) just a bit smaller than the diameter of a straw.\n\n2) Get a straw and force it through the hole in the lid. The straw should be made out of a fairly strong substance.... perhaps like a curly straw. The curly straws actually have straight sections. If the straight section is at least 3 inches long, it should work to go ahead and cut it. If the straw jams too tightly in the lid, it will obstruct the flow so just cut the hole slightly bigger until you get the right fit. We just want the straw to fit REALLY snug.\n\n3) position the straw so only a small length of it is pointing out the bottom of the cap (the longer portion should be sticking out of the top of the cap acting as a nozzle). Once the straw is placed, you could use a little epoxy or tape just to keep it from coming out.\n\n4) Get a small water balloon. Lower it into the opening of the bottle but DON'T LET IT FALL IN!!!!  While holding the opening of the water balloon above the opening of the bottle (with the rest of the balloon hanging inside the bottle), fill the balloon with vinegar so that it takes up about half the volume of the bottle. Once this is done, tie off the top of the water balloon and let it drop into the bottle. You may want to hold the bottle on it's side so the balloon doesn't smack the bottom of the bottle. Then slowly tip the bottle back up.\n\n5) Now, carefully fill the remaining space in the bottle with baking soda. (we don't want the balloon to pop YET)\n\n6) Put the lid back on the bottle and stick a piece of chewed gum just barely in the outside opening of the straw. This will preserve the baking soda by not letting any excess moisture in while the fire extinguisher is not in use. Make sure that the gum is not in too tightly or too far as we want to be able to remove it quickly.\n\n7) You are done!!!!! To use it just remove the gum and smack the bottle on a hard surface so the balloon breaks inside the bottle. When the balloon breaks, the vinegar and baking soda will mix, react, cause pressure, and the pressure will be released through the straw and in the direction that you point the fire extinguisher  : )\n\nHope this helps\nThanks\nJon
185600
How to make a simple Van de Graaff Generator\n\nITEMS:\nPlastic Tupperware (microwave oven safe)\nSome wires\nNail\nSmall DC motor \nPiece of PVC pipe (approx. 3.8 cm in diameter)\nBroad rubber band \nWooden skewer\nPlastic bag\nRoll of tape\nSoft drink can\nMineral water bottle\n2 3volt batteries\nBattery holder (optional)\n\nPutting it together:\n1) Cut a hole in the middle of the bottom of the plastic container.\n2) Glue/tape the motor to the lid, making sure the shaft is at the centre of the lid.\n3) Using a hot nail (can be heated at the stove), make two holes near each other for the wires of the motor\n4) Thread the wires through the two holes (the two wires will connect to the batteries)\n5) Cover the container with the lid. (Inverted container in this case)\n6)Make another hole, perpendicular the motor shaft\n7) Thread another wire through(this will be your ground wire) \n8) Make the appropriate measurements for cutting your PVC pipe length and grooves(where the stick will rest)\n9) To make the roller, just stick tape to your stick and go round and round and round.\n10) Place the PCV tube on the lid, perpendicular to the motor. \n11) Thread the stick thru the rubber band and place it in the grooves.\n12) Make sure both rollers are parallel to each other when you thread the bottom of the band to the other "roller"\n13) Cut the top of the soft drink can.\n14) Cut both ends of the mineral water bottle off, making sure that it isn’t shorter than the PVC pipe.\n15) Make a hole near the top of the bottle.\n16) Strip some wire, twist it, and poke it through the hole.\n17) Electrically connect the copper wire to the soft drink can.\n18) Tape everything in place.\n\nWhen you put everything together, you get a crude Van de Graaff generator. Make sure the combs (end of wires) are near the belt and rollers. Make sure that when you run it, the belt doesn't slip off. If it does, make sure both rollers are parallel to each other. Also, try to superglue the motor to the Tupperware lid.\n\nWhen you first run it try taping strips of tissue paper to the can. It should start to rise seconds after the batteries are connected. If this fails, put your finger near one of the tissue strips. The strip should be attracted to your finger.\n\nPlaces with high humidity can be a real problem for electrostatic experiments. Try working in an air conditioned room to help overcome the problem.\n\nThe last two links are the best ones and both include detailed step by step process with pictures.
1052452
make anything out of the following\nperiscope\nvolcano (Although I don't suggest this - it is a very old project and maybe many will turn up using this)\nA mini hovercraft or hot air baloon (info can be found on net)\nI don't know what it is called but if you know that thing in which we have to take a small hoop across a wire (which is not straight) without touching it. If touched, it will make a sound.\n\nIf none of this suits you, you might watch Backyard Science at National Geographic Channel
626248
How about a caterpillar? Check the crafts dept. at Wal-mart. Use stryo balls for the body, just glue five or six together in a line,  which you'll need to paint of course, add pipe cleaners for legs, just use wire cutters to cut them in thirds and just stick them in and bend them down, then use the stick-on googley eyes that they sell, and add a colored piece of paper cut for the mouth, and two toothpicks painted black and stuck in his head for antenna. Easy, and uses 5 materials
739656
draw a really thick line at reachable height and he will rocket in the air