Naked Science Forum

General Science => General Science => Topic started by: paul.fr on 20/05/2008 14:06:19

Title: Why does hydrogen peroxide, added to yeast, relight a glowing splint?
Post by: paul.fr on 20/05/2008 14:06:19

This is what i did, but why does the skewer should flare up, bursting into flame?

Pour some hydrogen peroxide into the glass. Sprinkle some of the yeast into the peroxide and give it a stir. Very quickly you will see bubbles rising, producing foam on top of the liquid.

Light the end of the wooden skewer, and let it burn for a moment. Then blow out the flame. If you blow gently on the burning end, you should see a red glow. It is still burning, but not flaming. Carefully bring the glowing end of the skewer up to the larger bubbles in the foam.

The skewer should flare up, bursting into flame.
http://www.thenakedscientists.com/forum/index.php?topic=6730.msg174769#msg174769

Title: Re: Why does hydrogen peroxide, added to yeast, relight a glowing splint?
Post by: graham.d on 21/05/2008 13:20:40

I am not a chemist, but you are probably releasing oxygen from the H2O2. I expect there is someone here who can explain the reaction.

Title: Re: Why does hydrogen peroxide, added to yeast, relight a glowing splint?
Post by: lightarrow on 21/05/2008 19:16:24

Quote from: Paul. on 20/05/2008 14:06:19

This is what i did, but why does the skewer should flare up, bursting into flame?

Pour some hydrogen peroxide into the glass. Sprinkle some of the yeast into the peroxide and give it a stir. Very quickly you will see bubbles rising, producing foam on top of the liquid.

Light the end of the wooden skewer, and let it burn for a moment. Then blow out the flame. If you blow gently on the burning end, you should see a red glow. It is still burning, but not flaming. Carefully bring the glowing end of the skewer up to the larger bubbles in the foam.

The skewer should flare up, bursting into flame.
http://www.thenakedscientists.com/forum/index.php?topic=6730.msg174769#msg174769

The H2O2 with yeast clearly releases oxygen. In oxygen athmosphere things burn much more rapidly so the skewer's temperature increases generating the flame.