Question about making Agarose gel for electrophoresis

[Really Lost]

When you are making an agarose gel at one point the mixture of agarose and water might be heated in a microwave. Why would you also put in a glass of water in the microwave? I think some how the glass of water some how prevents the agarose mixture from boiling over. But how does this really work?

 

This may be a chemistry physics question.

[CharonY]

Not everyone is doing that. At least I do not know anyone who does it. What I could imagine is that it is an attempt slow down the heating, but then you may get the same result by using a lower setting (though some may not allow that).

[Arete]

Never heard of that one. We just set the microwave to medium.

Don't screw down the lid of the Schott bottle... had a tech do that in a lab I used to work in. The results are spectacular, but undesirable.

[CharonY]

While we are at it, do not put the hot bottle near your eyes to check whether everything has been dissolved. Superheating is no fun, tight cap or not.