News
Researchers at the University of Rochester, US, have taken an elderly groups of rats on the rodent equivalent of senior citizens road trip to find out how air pollution breathed in by motorists might be harmful to health. Alison Elder and her team wanted to unders...
Questions

Why is it that when you pour cola in a glass with ice, there's more foam than when you pour it in a glass with no ice?
This is because the ice is sharp and is something called nucleation. Coke has lots of dissolved carbon dioxide in it, which is what makes it fizzy. When you put it in a glass, you'll notice that the bubbles all come from little spots in one place on the surface of the glass and they stream up in a stream. The reason that they do that is because there'll be a little area on the glass or a tiny imperfection that makes the glass slightly rough and it's easier for a bubble to form there. The carbon dioxide dissolved in the drink starts to come out of solution and come out as bubbles of gas at that point. If you put ice in the glass, which is very very rough and has lots of sharp edges, it creates an even bigger surface area with lots of nucleation sites and you get lots of gas coming out. This is why it becomes frothy.

Can two black holes merge together if they get close enough to each other?
Yes, can black holes can merge. When two black holes get quite close, it actually becomes inevitable that they'll end up spiralling in towards each other and merge together. This causes a massive energetic event. What you get at the end of it is just another black hole, but bigger. But what it can also do is form ripples in space. If you know anything about relativity, then you know that gravity is caused by bending of space. When you merge two black holes you get ripples, but so far they're only a theoretical idea and scientists are trying to look for them. If we could spot them, then that would really prove relativity.

Why does water bubble when it boils?
You have an element in your kettle and that gets very hot. Next to that element is water that turns to water vapour, which is 1000 times bigger than water because it's a gas. This bubbles up through the liquid.
Kitchen Science

Although it's freezing in England right now, on the other side of the world the sun is shining. So in honour of the sun-drenched Antipodes, Derek goes for a BBQ at the house of our very own Ozzie Hugh Hunt.
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Interviews
How Chillies trick your mouth into thinking it is hot and how this is related to tarantulas.
How doctors deal with pain, what painkillers do to you and what pain does to you.
Geoff Woods has been researching why some people are unable to feel pain, and how this could be useful for medicine.
Anna looks at how colour is involved in finding and choosing a mate, in the animal and human kingdoms.
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