A cool project that i need ideas for:)

[zkid15]

ok so heres the deal, in school im planing on making a water rocket and having a second fuel system(diet coke and mentos) so the water will propel the rocket up and then the second fuel system will actvate shooting it up farther...the only thing is...i have no idea on where to start on the activation of the second fuel system:(

 

any ideas???

[sanctus]

My thoughts:

Firstly

You have to find a way to attch the menntos in the bottle otherwise it will fly out with the first interaction with coke.

The hard part seems to be to put the coke inside the bottle with water without mixing and without touching the mentos too early. An idea which I don't know if it works is that you take a very thin plastic bag which you fill with coke and put inside the bottle, at mthe bottom. Then you take a metal wire (very thin to not increase the weight) and make two holes in the bottle just above the thin plastic bag and put the wire through the holes so that if you turn the bottle around (ie in starting position) the bag lies on the wire. Now you put some tape on the hole just to nnot let escape air from there (stability).

Now you take one ore more mentes and bite them or cut them just so that they have a sharp corner. Now you take some glue put it on the sharpened mentos and with some chopsticks you try to stick it/them to the wire.

Now the theory is that the thrust of the water going out will push the coke bag against the sharpened mentos and if everything goes well the bag breaks and you have your seeked second fuel system coming into action.

Now the problem I see is that I don't know if the reaction is quick enough, in the sense is it enough that the cokes touches a mentos and it starts right away?

 

Another idea is you put the mentos and the coke already mixed in a bag (close it quick enough :confused: ) and put something else on the wire so that it will break during the "water thrust".

 

A general problem I see is: does the coke mentos reaction also happen when there is enough volume? I mean I only tried with a full bottle never with an 3/4 empty one.

 

Last suggestion: use out of date coke (it still works I tried only with 2 years out of date coke) because:

1) You don't waste something still drinkable

2) You have a better conscience

3) You might find it at a cheaper price or for free so you can make many tries.

[zkid15]

thnx alot! thats a really good idea...in theory...i could c that possible

still...if any 1 still has ideas...dont hesitate:))

[freeztar]

Your best bet is to experiment with lots of variables. For instance, how do the mentos react with DC when pulverized vs. whole? How many mentos are needed for significant propulsion? How can weight be reduced?

 

As far as a mechanism for timing the mentos delivery, I would suggest you try gelatin capsules stuffed with pulverized mentos, placed into the DC just before launch.

[zkid15]

WOW THATS GOOD!!!

man im so happy i found this site!!!

freeking smart people here!

thx men...im ganna sharpie u guys on the side of the rocket in honor of your ideas!!! lol thx for giving me exelent ideas and of corse...if u have more dont hesitate to share:))

[freeztar]

I have not tested any of the ideas I presented.

I do not know gelatin degradation rates in the presence of a semi-strong acid such as DC. It might leak quicker than you desire, or it might not leak quick enough. Hence, experiment!

And of course report the results back here for documentation. Science needs data! :)

[zkid15]

lol definatly :) youd think DC would make it disolve quiker...id think so at least i dont no...also if the DC is expired(cheap or free) would the lack of carbon make the capsul disolve slower? i will find out lol

[sanctus]

More an answer to freeztar: I know by experience that one mentos is enough.

 

zkid: does expired coke imply lack of carbon?

Also did you think about the fact that usually you are standing under the rocket when it starts? So I suggest you put on a hat or something, unless you want to make your hair like a punk...(I wonder if coke works better to make the "crest" than what heard is used usually: the white of an uncooked egg...)

 

WOw, I just saw where you live do you still see something of the bridge or is it all gone?

[zkid15]

you saw where i live?

i dont know...if the DC is flat then isnt there a lack of carbon?

also...where would i get capsuls to put the mentose in?

[zkid15]

 

 

Also did you think about the fact that usually you are standing under the rocket when it starts? So I suggest you put on a hat or something, unless you want to make your hair like a punk...QUOTE]

 

 

lol my hair is already semi punk so i dont have to worry about that and second...my teacher is the one under it so no worries for me:P

[freeztar]

you saw where i live?

I lived in Olympia for a few years, so I'm pretty familiar with Tacoma. One of my best friends is a firefighter there.

i dont know...if the DC is flat then isnt there a lack of carbon?

That would be my assumption based on the fact that the carbon dioxide slowly permeates through the plastic over time.

also...where would i get capsuls to put the mentose in?

From your local health food store... They sell empty gelatin capsules so people can make their own herbal pills. They're pretty cheap too!

 

Sanctus: I assume you mean the Tacoma Narrows Bridge?

Tacoma Narrows Bridge - Wikipedia, the free encyclopedia

 

It was destroyed in 1940 and rebuilt in 1950.

[zkid15]

yea...there building another bridge right next to the narrows...they didnt tear it down...in fact it should be complete in fall...its pretty exiting:P its very amazing the building of a good size bridge:hyper:

[zkid15]

also i forgot...thx for the help on the capsuls...og btw...did u like living in WA?

[freeztar]

Yes, I loved WA! Hated the clouds though...

You couldn't ask for a better place to study ecology imho.

[zkid15]

lol i dont like it at all here...its too wet and im tired of waking up in the morning and looking out the window to see sadness lmao thats what constant rain every day in the winter has made me feel...but i LOVE the summers here! there perfect:))

[Michaelangelica]