Why does food on the hob bubble?

[kirkster501]

I had a tin of Heinz Soup on the hob and watched it slowly warm up and start to bubble.  It got me thinking.  Why does it bubble?  When it starts to warm up there is no air being sucked down from the surface to create these bubbles.....

[Bizibilder]

Because the liquid (water) reaches its boiling point and turns into a gas (steam).  It is the steam that forms the bubbles - usually below the surface as the temperature is higher towards bottom of the pan where the heat source is.

[ollypenrice]

Because the liquid (water) reaches its boiling point and turns into a gas (steam).  It is the steam that forms the bubbles - usually below the surface as the temperature is higher towards bottom of the pan where the heat source is.

You've invented the Bean Engine!

Olly

[Dave Lloyd]

Less dense than the surrounding medium so will be be displaced by the liquid sinking towards the centre of the earth. This forces the bubbles to rise to the top.

[faulksy]

as said, the heat source is turning the liquid into gas, in this case steam thats what the bubbles are