whats a rely cool science project that's is not hard a easy one and i don't wanna buy some expense stuff

Answer 1

Meth Lab

Answer 2

Make a trebuchet.

You can get a CD with the plans for $20. Then you just need the wood and nails. Scale it up or down as you want. If you have the time and want to go really cheap, request a copy of the book through interlibrary loan. Interlibrary loan can get you any book from any library on the planet, if you can wait for it to get to you.

Now I don't think you can make a FULL SIZE treb, ( Large mideval siege weapons tend to make neighbors nervious, and they complain to the neighborhood association, etc.) but you can make a small treb, and then run an experiment with it where you vary the amount of rocks in the basket, but keep the sling length and thing you are flinging the same and see how your distance varies over several shots. Then you can vary the sling length, keeping the counterweight and object flung the same, and measure distance and direction of what you fling. Then vary what you throw, keeping the sling length and counterweight the same and measure the results. Then do some fancy charts to explain it all (Science fair judges love fancy charts).

http://www.trebuchet.com/

http://www.trebuchetplans.com/

Answer 3

Buy several kinds of wire - stainless steel, ordinary galvanized, black wire, copper, brass, etc. As close to the same size as possible plus examples bigger and smaller if you wish.
Set up two rails about 10-20 feet apart outdoors rigidly mounted. Half way between them have a flat surface- concrete block, board, driveway, that will not move. Measure the exact distance. Figure out how you are going to fasten the wire ends to the rail. On the ground, mark lengths of wire that are exactly the distance between the rails plus 1" then add enough beyond that length at EACH end to fasten (e.g. if you need 6" to tie wire around screws, measure 6" from one end, then measure the length between the rails, then add 1", then add 6" and cut.)
Pull the wires straight. Mount the wires side by side with the length+1" marks exaclty aligned and note temperature at the wires.
The wires will sag in the middle, like telephone and power wires do. Use a yard stick to measure from the flat surface up to the wires without pulling on the wires. Note the time and temperature. Repeat measurement at various times of day and on succeeding days, noting temperature changes.
Report on changes of height with temperature and see if you can compute changes in length and compare that to reported coefficient of expansion of the metals and see whether wire diameter (size) affects the results.
When done, coil up the wires and save for future use - net cost, nothing for wire, cost of mounting if any.

Answer 4

mix baby powder or cornstarch with water, it looks really cool...run your fingers through it. or you could wrap insulated wire around a nail or something iron, then hook the split ends to a 9 volt battery. it makes a magnet.

Answer 5

Mentos dropped in a full two litre diet coke bottle...


...What is the foaming mechanism?

Answer 6

which browns faster? Bananas left at room temp or bananas in the fridge? and why?

Answer 7

Old fashion POTATO CLOCK.