I know sugar has a high flamable and explosive rate......?

Question

and know it is usually micro size dust in the air. But a couple of weeks ago I boiled a mug of water for coffee and put a spoon full of sugar in as I took it out. It turned into a volcanic eruption. Since then tiredly I have done it a couple of other times.......So I caught on and stopped. But why is this happening?

So I thought it was just the sugar.....nope thinking I could save the few seconds I put in a spoonfull of instant coffee and yup I burned my hand and made a huge mess! So it just isn't the sugar what is it?

Answer 1

It's called superheating.  You can heat water above its boiling point without it boiling.  Water needs some type of disturbance to seed the boiling effect.  Usually this is dirt or scratches in the pan you are heating.   Microwaves have a way of heating the water at the top or the center of the cup so that the roughness of the cup does not touch the superheated water and it does not boil.  When you add something rough to it (sugar, instant coffee, dirt, whatever) it causes it to boil.  

You can also cause it to boil by stirring or shaking it.  It's very similar to the type of disturbance needed to get the fizz out of pop.  You can either shake up the pop bottle, or you can add sugar or salt or dirt and it will foam all over the place.  That's what they'e always doing on youtube with coke and mentos.  It works with anything, it's just an advertisement ploy to get you to specifically buy coke and mentos.

But a warning:  Usually superheated water spontaneously starts boiling when it gets hot enough.  Under just the right conditions, i.e. really clean glass and clean water and few vbrations, you can superheat your water too much so that it explodes when you take it out of the microwave.  It's fun to play around with until you put in your instant coffee and boiling water explodes in your face.  People have been seriously injured by this.  Any time you stick something in water that's been heated in a microwave, keep your face away from it when you put it in!

Edit:  It is pretty rare, but very dangerous when it happens.  See the article below.  I have read that if you want to be safe, put something like a wooden stirring stick in your cup to keep it from superheating.  I just keep my face away when I add my teabag (and I admit to trying to superheat water in the micro because it's cool looking when it explodes), but that's hard to get kids to do because water looks so harmless.  Chemists have the same problem when they cook small amounts of chemicals.  They use either a wooden stir rod or a "boiling stone" to keep their heated test tubes from "popping".  I remember in organic chemistry lab when someone would forget the boiling stone and the whole experiment would "pop" and spill all over their lab table and hours of work would be ruined.

Answer 2

No, its something else in the coffie.  test around