RMCybernetics - Experiments

Exploding Water

This experiment demonstrates how a substance can change from a liquid to a gas in an instant! A cup of hot water will immediately explode when a small amount of a very cold alcohol based substance is added. Great care must be taken when performing this experiment, and the cold liquid should be added remotely or from behind a safety screen.

As soon as the liquid is added the entire cup of water will explode launching hot water and probably the cup into the air, so it is important to wear safety goggles and to be a good distance away when it happens.

The liquid is an alcohol based aerosol called 'Tetrafluorethane Dimethyl ether'. The 'Dimethyl ether' part is an organic compound used as propellant in other aerosols and is used with propane for cryogenic freezing.

This substance is found in aerosol cans in DIY or electronics shops but its expensive at around £10. It is commonly used for rapidly cooling electronic parts, removing chewing gum, or for freezing water in pipes that need to be cut. In the shops it can usually be found under the name "Freezer Spray".

How it's Done

The freezer spray is designed to evaporate rapidly as it is sprayed onto a surface as this draws heat away from it very quickly. For this experiment the freezer spray must be collected in liquid form before it can be used.

This is done by holding the nozzle in the plastic lid or similar container like shown on the left. The button is then pressed lightly so that the spray starts to come out slowly and collect in the lid. The first bit of liquid will probably evaporate quickly, but as the lid cools down it becomes easier to collect. The amount to collect will depend upon how big the cup of water is and how long it takes to go from collection to adding it to the water.

The liquid is poured in to the hot water using a long stick

Once the liquid is collected it is tipped into a cup of hot water at a distance. It is important that the collected freezer fluid is tipped in at once and not dripped in. If it is added too slowly it will just evaporate before any violent reaction can occur.

Sometimes only fizzing and sputtering occurs, but when done correctly the reaction is immediate and quite powerful.

Important Safety Notes

- The water needs to be hot but not boiling or hot enough to scald.
- The cup holding the hot water should be a light weight plastic type like those from a vending machine.
- The freezer spray should be added to the water away from people, animals, or anything else that would be damaged by hot water.
- The spray should be used outdoors in a well ventilated area away from sources of ignition.
- Safety goggles, gloves and other protective gear are recommended to avoid injury from spilling or splashing of the collected freezer spray.

Questions and Comments on the Exploding Water Experiments

The information provided here can not be guaranteed as accurate or correct. Always check with an alternate source before following any suggestions made here.

monica

Tuesday, 24th April 2007 5:40am - No.1194

awesome! How clever.

Commodore

Monday, 3rd September 2007 12:53am - No.1688

Removing the nossle from can (only if it easily lifts off) Use a pin to enlarge the exit hole. This will cause the liquid to eminate less dispersed, making collection easier.

If collected fluid is placed in a 'water bomb' ballon, would the ballon last long enough and also burst in the hot water to allow safer delivery? Maybe expanding ballon due to temp. diff. would make this impractical.

**Evil Genius**
Combine this project with a peltier cooler, to MOD a water pistol. Then you can hold up your local Costa ;)

CoNfUsEd

Saturday, 5th July 2008 6:47am - No.2886

I dont really get it?? Please help me!

Tyesha c.

Friday, 14th November 2008 1:47am - No.3338

what would happen if you add only cold water and hot alcohol?

RMCybernetics

Saturday, 15th November 2008 1:02pm - No.3343

You would have a pretty tasteless warm beverage.

ALICIA

Saturday, 24th January 2009 7:53am - No.3504

I REALLY ENJOYED THIS EXPERIMENT! IT WAS REALLY INTERESTING!

maxine nd joana

Sunday, 17th May 2009 10:19pm - No.3818

the exploding water was AWSOME!!!! very nice but wat is freezing spray i have no idea wat that is please tell us wat it is..:)

RMCybernetics

Monday, 18th May 2009 12:03am - No.3819

Freezer spray is used for doing plumbing jobs where the water can be blocked by freezing a section of pipe. You can find it in most DIY stores or electronic comonents suppliers. The spray is made from a volatile chemical that eveporates very quickly and taks heat away with it.

marco

Monday, 29th June 2009 1:52am - No.3943

What's the physical principle behind that?
Is it something similar to adding water to frying oil?

RMCybernetics

Wednesday, 1st July 2009 8:22am - No.3945

Yes. The freezer spray expands rapidly when it hits the hot water which causes the explosion. Some of liquid is not in direct contact with the water due to a cushion of gas, which is why it will crackle sometimes or not explode immediately.

Back To Experiments

Back To Projects

Home

PWM Circuits - Electronic Components - High Voltage Devices - DIY Science Projects