Greetings fellow people,

This is one prank which cannot be missed if you're a chemistry geek (well, it doesn't matter) and want to get some sweet revenge against a misdeed!

This prank is a projectile (actually, a bottle cap) launcher which launches the bottle cap upto ~75 feet!

Great thanks to Shubhaang Digge and Tushar Saykar who made this project a success!

Step 1: Materials Required

This project requires things much lesser than you anticipate.

I'll just list down the things you would need in order to make this prank a success.

For one explosion you would require:

~50 ml of 6% Hydrogen Peroxide - Usually available at a chemist's.
A pinch of Potassium Permanganate -Usually available in school labs or can be easily ordered online.
A nice 200 ml polyethylenetetraphthalate bottle (Don't worry, its the tough plastic bottle you get drinks in).It can be anything- like a Minute Maid bottle or something.
An accomplice/friend who's willing to help you in your prank. (Optional)

Step 2: The Common Misconception- Get It Cleared!

Everyone knows about bombs. But what everyone thinks is that a bomb is something about fire, smoke, deaths, explosions, etc. Minorly true. But in this case, our bomb is ECO-FRIENDLY! It's got NO FIRE, NO SMOKE and NO DEATHS (except in extreme cases where the bomb is detonated in front of someone's face).

If it ain't got any fire, smoke, or any deaths, doesn't make it a dud bomb or something which is like a party popper. Its got something in it which will blow your minds!

Step 3: Procedure- the Making

The D-Day has finally come when you are in the battlefield and the last of your army and have the final chance to deploy the bomb- it's a do or die situation. Well, you're obviously gonna do it otherwise why would you waste your time reading this instructable!

So here's how it goes:

First, rip off the plastic labels off the bottle. This will make the reaction very visible to the user. (It's too cool to watch, nothing else)
Fill the 50 ml of 6% Hydrogen Peroxide in the bottle.
Ask your friend to hold the bottle containing the peroxide along with the cap (unscrewed).
Then take a pinch of the Potassium Permanganate and add it to the bottle.
This part has to done faster than the speed of light (exaggerated). As soon as the crystals are added to the bottle, screw back the cap on the bottle. This should not take more than a second (actually).
Now, there will be an instantaneous reaction between the two chemicals and there will be evolution of steam and the bottle will get really hot- this is a very exothermic reaction.
The bottle should be getting firmer due to the steam pressure building up inside. (This won't work if your plastic is thin, get a tougher plastic, enough to handle the pressure).
Put the bottle on the ground and give it a few shakes with your leg. The bottle would now get stiffer than anything you ever saw.

Now for the best part! DETONATION

Step 4: Procedure- the Detonation

Now that the bomb is armed and ready, gear yourself up for detonating the device yourself or get your friend along if you don't wanna be visible while it is being detonated.

To detonate:

Put the stiffened bottle on the ground and point the cap to the direction you want to launch the bottle cap.
Now on the side of the bottle which doesn't have the cap on, put your left leg on the bottle mid-part and try to make a strong grip on it.
Then, put your right leg midway across the bottle cap.
With a jerk, yank your right leg back and try to open the bottle cap in a go. (Remember to do it as quickly as possible)

BOOM! THAT'S IT!

Step 5: Precautions

Pranksters, here are some precautions you better read and take care of before deploying the bomb.

You would need to close the bottle cap as soon as you mix the Potassium Permanganate with the Hydrogen Peroxide because if the steam escapes, the project would render useless as there would be no steam to inflate the bottle.
TIP: Doing this in an empty space such as a basement or an empty parking lot would make the sound echo and you would actually see the range of the projectile firing.

Step 6: How Does It Actually Work?

Dear readers,

Let me tell you what's going on inside the bottle.

See, when you mix the Potassium Permanganate crystals to Hydrogen Peroxide, there is an intensely exothermic reaction. There is formation of Manganese Dioxide, Potassium Oxide (which gets hydrolyzed to Potassium Hydroxide) and finally, tons of steam!

This steam causes the bottle inflate and causes the inside pressure to rise.

When the bottle cap is released with a jerk, the steam inside (at a very high pressure), gets to come out to a low pressure (relatively) surrounding, causing a shock wave to form.

You can very well see this shockwave clearly in the video. Also, if you download the video and watch it on VLC Media Player, you can slow down the video and see the shockwave (at time ~0:56).

Step 7: Enjoy Blasting!

This bomb is a potentially safe one which has practically no risk, when the instructions would be followed ;)

You can deploy this one in any housing society, office, school, hospital or any other place and yell 'FIRE!' or something which is sure to cause instant havoc and get immediate attention!

If you happened to get caught, don't worry! Just say, 'I was doing for the sake of science.' or 'Don't you want me to score good marks in chemistry?' or 'This is an educational experiment.'!!

This way, one can learn chemistry and have fun in an unusual cocktail which is in the form of a bomb!

ENJOY BOMBING!