karlboll · 2 weeks ago
They sink, because they're heavier than the liquid, and then they float, because the carbon dioxide forms bubbles on the skin making it more buoyant. Yay science!
My favourite is electrolysis to make hydrogen with water, sodium bicarbonate, a 9 volt battery and two pencils.
If you want to do it look it up but it goes something like this;
In a glass of water, mix in a little sodium bicarbonate.
Remove some wood from both ends the pencils so the graphite is exposed and placed them in the glass.
Touch the battery terminals to the ends of the pencils.
Bubbles should form on the submerged pencil ends. One side will produce oxygen and the other hydrogen. Try to figure out why this is happening and what side produces what.
Be careful. Hydrogen is flammable but this shouldn't create any significant quantities. But it's always best to be safe so wear glasses.
bensen · 2 weeks ago
Thank you mum and I both like your answer :)