Introduction: Safe Video Demonstration Sodium and Potassium Exploding in Water

The demonstrations of many remarkable experiments include a high safety risk (e.g. the reaction of large pieces of sodium/potassium with water; the reaction of potassium with liquid bromine; the reaction of sodium with concentrated sulfuric acid, etc.). Chemistry teachers and instructors are usually reluctant to perform experiments that include a hazard. As a result, a number of fascinating experiments remain unknown to the public.

A very violent reaction of sodium and then potassium with water.
2Na + 2H2O --> 2NaOH + H2

2K + 2H2O -->2KOH + H2

Small pieces of these metals are dropped in water.


An Villain (author)2009-09-28

elephant noises.

antienoob (author)2009-09-01

is this video also on youtube because my computer is playing up and i cant view it.

codongolev (author)2008-07-09

did anyone notice that the potassium made the water green, but then it exploded and turned purple?

lobo_pal (author)codongolev2009-06-20

That was a Ph indicator. It turned purple because of the presence of NaOH in the water after the reaction.

high1 (author)codongolev2008-11-26

yeah, I did, it is strange...

adsa (author)2009-06-17

As an alternative fill a beaker with water to create a positive meniscus. Add 2-3 drops of phenolphthalein to the water and then place a piece of filter paper on the beaker ensuring the paper absorbs some of the water. Place some Na onto the paper, stand back and enjoy. Unfortunately my school is not allowed to have K or Na anymore, so keep your videos coming!!!

FunkNattidelic (author)2008-03-15

I noticed that the thing that the crap was put in was green before the explosion and purple after the explosion. any body else notice that??

Scar21 (author)FunkNattidelic2008-03-20

Yeah, you can even see the color change when it goes to slow motion. And the thing the crap was put into was water. And the crap is Potassium. We did this at our school, but with sodium instead. It caught fire, but not actually exploding like that :D

conrad2468 (author)Scar212008-03-20

go to to get some sodium and other reactive elements plus other junk that you might want

I think they added a Ph tester to the water since water is normally green with it. After potassium hydroxide is produced, it turns purple or pink cause I think potassium hydroxide or whatever is made is somewhat acidic...?

Berkin (author)metroidfreak1082008-11-21

The pH tester was phenolphthalein, a chemical previously used in - believe it or not - laxatives. :D (author)Berkin2009-06-11

i thought phenolphthalein was clear until theirs an alkali present?

Berkin (author)mr.space2009-06-11

Yeah, kinda.

Scar21 (author)conrad24682008-04-01

That's right. We did that too. I remember now.

codongolev (author)2009-04-02

just shake to combine the potassium with the water, draw while you still can, then run and hope it doesn't blow up! if it doesn't, then keep drawing in purple. if it does, then hey! abstract art. (author)codongolev2009-06-11

that probably universal indicator solution, green is neutral, the purple indicates a strong alkali solution i.e. potassium hydroxide

THESTU (author)2009-04-11

super cool.

fd93 (author)2008-04-18

we also did that but we used some other alkilane that i cant remember. i think ribidium or cesium it was realy ausome.

Tubetech762 (author)fd932009-02-12

Try lithium if you can get any. It isn't radioactive like cesium and the reaction is quite entertaining. Lithium is VERY reactive and when contact with water the reaction is explosive so be VERY carefull

fd93 (author)Tubetech7622009-02-12

if you have lithium my fave is to use it in fireworks makes great deep reds

Tubetech762 (author)fd932009-02-13

I was reffering to metallic lithium but in this form it is hard to find, as few people are experianced enough to handle it safely. But you are correct lithium makes a beautiful red

Holden_vy_s (author)fd932009-02-10

I HIGHLY doubt you used Rubidium. And i doubt you used Caesium either, they were most likely Sodium or Potassium.

fd93 (author)Holden_vy_s2009-02-10

ya i have since checked with my teacher it was like 5 grams of potassium

heavy.metal.nguyen (author)fd932008-05-11

I doubt you used rubidium in a school science experiment. Alkali metals react very violently when it reacts with water.

looking4ideas (author)2008-02-21

We did this at my school but with a much smaller piece TT__TT This is much cooler

cotton (author)2008-02-08

dam thats coo;l

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