Need some help for a mentos+diet coke experiment for my class!!

[DigMe]

So I do the mentos+cola thing to demonstrate to my 4th graders that gas takes up space. In the past I've just done a freehand launch where I slammed it on the pavement and let it go. I've gotten some good launches like that. One took a sharp turn though and headed right at some kids on the playground once. So now what I'm trying to do is I've got a 4 ft long piece of iron pipe that is about 6" in diameter and I want to launch the cokes out of it artillery style. I did some practice runs tonight though and no matter what I could not get them to launch out of the pipe at all. Some of them would just barely make it out of the end and some would not make it out at all. I would drop them in and let the cap end poke out of the bottom. Then I'd slam a big breaker bar into the cap to get it to pop off.

When you freehand launch them they can fly pretty high with quite a bit of gusto but I couldn't get anything like that out of the tube.

Any ideas?

bc

[Josh Ryan]

http://www.youtube.com/results?searc...ype=&aq=-1&oq=

a few videos to watch?

[GeneralElectric]

I know a good one, I used to do this to an exgirlfriend all the time as a joke since all she would drink was diet coke.

You'll need:
A needle
Fishing line
Scissors
Mentos
Bottle of diet coke

Take the needle and poke a hole through the middle of a mentos. Thread a piece of fishing line through it and knot it so it doesn't slide down.

Dangle the mentos into the top of the bottle (but don't let it drop) and pull the string towards the bottom to bring the Mentos to the lip of the bottle opening. Screw the cap on tight, all while holding down the string.

Trim the extra fishing line. You shouldn't be able to see the mentos below the cap.

When you open it, it drops in.

Lulz.

[CanadaMan]

Have you tried putting a backing plate and slamming it into the tube as you would the ground? Basically using the tube as a guide so it doesn't go flying at the wee little ones but the same concept as before.

[Mark Latimour]

Originally Posted by DigMe

So I do the mentos+cola thing to demonstrate to my 4th graders that gas takes up space.

Any ideas?

bc

You want to demonstrate that gas takes up space? That's easy. Cut the cheese at the front of the classroom and tell your kids to put up their hands as they begin to smell it. When the kids at the back put up their hands say "see, gas expands throughout the room and thus takes up space". No need to endanger the kids with flying bottle rockets.

[DigMe]

Originally Posted by Mark Latimour

You want to demonstrate that gas takes up space? That's easy. Cut the cheese at the front of the classroom and tell your kids to put up their hands as they begin to smell it. When the kids at the back put up their hands say "see, gas expands throughout the room and thus takes up space". No need to endanger the kids with flying bottle rockets.

Yeah but that's way more fun for me than for them. I want them to have some fun too...not just smell my stink bombs.

bc

[DigMe]

Originally Posted by Blisshead

http://www.youtube.com/results?searc...ype=&aq=-1&oq=

a few videos to watch?

Those are all free-hand. None of them that I saw on YouTube were shot out of a tube.

Originally Posted by GeneralElectric

I know a good one, I used to do this to an exgirlfriend all the time as a joke since all she would drink was diet coke.

You'll need:
A needle
Fishing line
Scissors
Mentos
Bottle of diet coke

Take the needle and poke a hole through the middle of a mentos. Thread a piece of fishing line through it and knot it so it doesn't slide down.

Dangle the mentos into the top of the bottle (but don't let it drop) and pull the string towards the bottom to bring the Mentos to the lip of the bottle opening. Screw the cap on tight, all while holding down the string.

Trim the extra fishing line. You shouldn't be able to see the mentos below the cap.

When you open it, it drops in.

Lulz.

You're worthless.

bc

[DigMe]

I could really use those Smash Lab guys about now.

bc

[MakiSupaStar]

Maybe you just have a case of a narrow urethra.

[mfgl]

perhaps a long tube like a mortar, shake it up and shove it down the tube as hard as you can? when it hits the bottom maybe it will shoot out?

[Ripper]

use pvc and something at the end for it to blast against

[GeneralElectric]

Actually Brad, my mentos on a string thing could work, so long as you have protection. Simply put more than one mentos on the string. Upend the bottle without opening it so the mentos touch the diet coke. Put in a clear box or something.


It will explode.

[L-A]

Here is a reference about what not to do.

http://www.youtube.com/watch?v=lFf-kW1E0Tc

[Vorago]

Originally Posted by L-A

Here is a reference about what not to do.

http://www.youtube.com/watch?v=lFf-kW1E0Tc

Ugh...I think this isn't going so well...

[jive1]

bc went from fighting bull sharks, building security fences, and crying apache to being unable to shoot a menthos through a coke bottle.

Pitiful.

[Chunk-O-Funk]

Brad,

Have you tried using a nozzle with a bit more narrow opening? Just thinking a more concentrated stream of pressure will give the bottle the amount of thrust needed.

[DigMe]

Originally Posted by GeneralElectric

Actually Brad, my mentos on a string thing could work, so long as you have protection. Simply put more than one mentos on the string. Upend the bottle without opening it so the mentos touch the diet coke. Put in a clear box or something.


It will explode.

You're not getting the question. I have no problem putting the mentos in the coke bottle and closing the lid and all that. It's just that when I slide the coke bottle down the tube and then knock the end off when it gets to the bottom it's not taking off and shooting out the tube like I want it to.

bc

[DigMe]

Originally Posted by mfgl

perhaps a long tube like a mortar, shake it up and shove it down the tube as hard as you can? when it hits the bottom maybe it will shoot out?

Originally Posted by Ripper

use pvc and something at the end for it to blast against

I tried the tube thing but it wasn't shooting out.

I was thinking about PVC tube with a cap on the end and maybe a big screw or nail poking up in the middle but then I was thinking that I don't know if the hole made by the nail when it slams down would be a big enough hole to allow enough liquid out to actually launch it.

bc

[Happynoj]

Maybe try a shorter tube?

[DigMe]

Originally Posted by Happynoj

Maybe try a shorter tube?

It really shouldn't make any difference since I've seen these bottles shoot as high as 40 or 50 feet or maybe more.

bc