what makes some glass containers super heat proof and others crack under heat?

165 views

what makes some glass containers super heat proof and others crack under heat?

In: 5

2 Answers

Anonymous 0 Comments

Most materials expand when they heat up. Glass, in particular, is a really good insulator (doesn’t conduct heat well) so when you heat it up the surface that’s exposed to the heat it can get a lot hotter than the inside that hasn’t warmed up yet. That means different parts of the glass expand different amounts, which causes stress, which leads to cracking. Something similar happens if you take hot glass and cool it down quickly, like putting cold water in a hot glass dish.

However, it’s possible to design materials that don’t expand much with heat, sometimes called “low-expansion glass”. This involves mixing a bunch of other materials into the glass, often a lot of boron, when it’s called “borosilicate glass”. Most people know that by it’s trade name, Pyrex. Since this doesn’t expand as much with heat, the stress isn’t as high and it’s much less likely to crack.

Anonymous 0 Comments

It’s called borosilicate glass.

They are two materials – Boron and Silicon to the glass

When you heat things up, they get slightly bigger. When they cool down, they get smaller.

Regular glass expands a lot with heat. If one side of the container heats up and expands while the other side is cold – then it cracks.

But borosilicate glass expands less, so it’s tolerant of bigger changes.

Sometimes heating up a cold dish cracks it.

Sometimes cooling down a warm dish cracks it. Often glass will break when you wash it in the sink because the cold water suddenly cools it down.