Let's drop calcium metal into water.

[background nose]

[student in audience]: Bubbles.

[background nose]

-You see bubbles.

It bubbles kind of rapidly, so you can see your first chemical reaction of the year there too.

-[inaudible student question] -The one currently?

-[inaudible student response] -The previous one was magnesium; this one is the calcium.

-Whoa!

-Little puffs of gas being given off.

What you're seeing is the water vapor.

You're not actually seeing the gas that's being given off.

The gas that's being given off is hydrogen gas,

[it] turns out.

[background noise and inaudible student talking]

So how reactive they are with water is one way to test their reactity;

and that is actually what we are doing today. We're gonna react each of these with water.

The next three are so reactive, that they have to be stored, with water, that they can't be exposed to the air.

So they are stored underneath oil. It' gonna take me a little longer to get them out and ready to go.

Look like the reaction is mostly finished I still see a little bit of bubbling still going on right here.

I see a bubble that's popped there, but that means there's a little bit of calcium down here underneath. Yes?

Did I see a hand? I thought there was a question.