[tubercle]

If winning a prize is involved, make something that throws sparks. The judges will be impressed

 Just don't catch anything on fire

[tschmidlin]

Those are really cool projects, I might have to do this with my kids, science fair or not!

[jeffy]

Those are really cool projects, I might have to do this with my kids, science fair or not!

I'm thinking of doing some of this, kids or not!

[phillamb168]

I wonder if my 6-mo old is too young for me to get him a Gas Chromatograph. http://cgi.ebay.com/HP-5890-Series-II-Gas-Chromatograph-/380305273353?pt=LH_DefaultDomain_2&hash=item588bf5f209

[nicneufeld]

Here's something I remember doing as a kid...

Raw materials required:

Matches or lighter
4 empty, opened cans of same size (average size, like the normal canned corn can)
Wire Hanger
Duct Tape
rubbing alcohol
Tennis ball

The tennis ball should fit moderately snugly in one of the cans.

First take three of the cans...drill a largish hole (maybe 1 1/2"?) in the base of the can.  This will leave a baffle ring around the edges, this is fine.  Take the fourth can, and drill a small hole (maybe 1/8") in the side of the can near the base.  Then duct tape them tightly together, with the fourth can as the base, the others on top.

Bend the wire hanger so it constitutes a nice stand...mold the main hanger to prop the "cannon" up, and bend the hook straight so it sticks in the ground steadily.

Load the tennis ball into the end of the cannon, it should fit down into that first can.  Using an eyedropper, shoot a couple squirts (I really don't remember how much) of rubbing alcohol into the hole in the base.  Roll it around for 30 seconds or so, so it covers surfaces on the inside.  It will start evaporating within the cannon.  With the cannon facing a safe direction in the stand, touch a lighted match or lighter to the hole in the base. 

Boom!  I had a lot of fun with this when I was younger.

[phillamb168]

Here's something I remember doing as a kid...

Raw materials required:

Matches or lighter
4 empty, opened cans of same size (average size, like the normal canned corn can)
Wire Hanger
Duct Tape
rubbing alcohol
Tennis ball

The tennis ball should fit moderately snugly in one of the cans.

First take three of the cans...drill a largish hole (maybe 1 1/2"?) in the base of the can.  This will leave a baffle ring around the edges, this is fine.  Take the fourth can, and drill a small hole (maybe 1/8") in the side of the can near the base.  Then duct tape them tightly together, with the fourth can as the base, the others on top.

Bend the wire hanger so it constitutes a nice stand...mold the main hanger to prop the "cannon" up, and bend the hook straight so it sticks in the ground steadily.

Load the tennis ball into the end of the cannon, it should fit down into that first can.  Using an eyedropper, shoot a couple squirts (I really don't remember how much) of rubbing alcohol into the hole in the base.  Roll it around for 30 seconds or so, so it covers surfaces on the inside.  It will start evaporating within the cannon.  With the cannon facing a safe direction in the stand, touch a lighted match or lighter to the hole in the base.  

Boom!  I had a lot of fun with this when I was younger.

Hah! Cool! But remember, You'll put an eye out! How's that larger hole figure in to everything? Can this be used to annoy squirrels?

[Hokerer]

Lighter Fluid also works well in that application.  Also, we would squirt the lighter fluid into the cannon and then put the ball it.  Lots easier than trying to get the fluid into the little touchhole.

[nicneufeld]

True...the eyedropper helped in that regard.  I'm sure this could be refined if one sat and thought it out a bit more...perhaps an integral trigger mechanism built off of a trigger lighter, etc., I just remember the way I made it as a kid, which has some sentimental value.

I'm not sure if the baffles are strictly necessary, but I think all that surface area helps because the alcohol evaporates more quickly when thinly spread out on surfaces.  When its evaporated, it combusts quite nicely!

I recommend airsoft guns for squirrels....particularly if you're not keen on eating them.  Only hit one once, and he was sure annoyed at me.

[tschmidlin]

I wonder if my 6-mo old is too young for me to get him a Gas Chromatograph. http://cgi.ebay.com/HP-5890-Series-II-Gas-Chromatograph-/380305273353?pt=LH_DefaultDomain_2&hash=item588bf5f209

I'm not . . . PM me for a shipping address.

[punatic]

how about biofuel? you could even distill it to make ethanol.

Did you get the microscope? You may be able to use that to show growing yeast.

I wonder when I'll have to do a science project for one of my kids.

Kai

YOU SAID THE D WORD!

[punatic]

Here's something I remember doing as a kid...

Raw materials required:

Matches or lighter
4 empty, opened cans of same size (average size, like the normal canned corn can)
Wire Hanger
Duct Tape
rubbing alcohol
Tennis ball

The tennis ball should fit moderately snugly in one of the cans.

First take three of the cans...drill a largish hole (maybe 1 1/2"?) in the base of the can.  This will leave a baffle ring around the edges, this is fine.  Take the fourth can, and drill a small hole (maybe 1/8") in the side of the can near the base.  Then duct tape them tightly together, with the fourth can as the base, the others on top.

Bend the wire hanger so it constitutes a nice stand...mold the main hanger to prop the "cannon" up, and bend the hook straight so it sticks in the ground steadily.

Load the tennis ball into the end of the cannon, it should fit down into that first can.  Using an eyedropper, shoot a couple squirts (I really don't remember how much) of rubbing alcohol into the hole in the base.  Roll it around for 30 seconds or so, so it covers surfaces on the inside.  It will start evaporating within the cannon.  With the cannon facing a safe direction in the stand, touch a lighted match or lighter to the hole in the base. 

Boom!  I had a lot of fun with this when I was younger.

Potato cannon. 
PVC tube - propane grill spark igniter - hair spray propellant and potato projectile.
Standard fare at Troop 65 campouts.

[loopy]

Potato cannon.
PVC tube - propane grill spark igniter - hair spray propellant and potato projectile.
Standard fare at Troop 65 campouts.

+1000. 



the same 5 year old from above science fair story.... 

[punatic]

Every once in a while I catch him trying to figure out how much higher the CO2 balloon needs to be so when dropped, they hit the floor at the same time.

Galileo - David Scott - Falcon Feather - Hammer - Hadley Rille

[phillamb168]

I wonder if my 6-mo old is too young for me to get him a Gas Chromatograph. http://cgi.ebay.com/HP-5890-Series-II-Gas-Chromatograph-/380305273353?pt=LH_DefaultDomain_2&hash=item588bf5f209

I'm not . . . PM me for a shipping address.

You mean PM you with MY shipping address. Thanks a bunch, I knew you guys were a generous bunch!

[a10t2]

I guess I'm late to the party, but how about looking at fermentation? No reason to explicitly tie it into beer. Sugar water and yeast in a jar, put a balloon on top. Using different amounts of sugar, show that the size of the balloon is proportional to the amount of food the yeast have. Explain that yeast eat food and expel CO2, just like people do. Tie it into the circle of life on our fragile planet. Science fair judges eat that s*** up.