The Naked Scientist, Chris Smith offers listeners the opportunity to satisfy their curiosity about the world they live in and to find out more about the weird and wonderful laws of nature and the intricacies of the human body.
This Friday, the Naked Scientists lets us know how birds find their way around.
This week's science story:
Scientists think that birds have a form of an in-built compass that enables them to tune-in to the Earth's magnetic field.
But there's still a problem with that explanation: it would enable them to navigate north to south by following the strength of magnetic field lines, but it wouldn't tell them where they were around the planet in an East-West direction.
Writing in Current Biology, Holland and his colleagues used a coil apparatus to expose groups of birds to an 8-degree counter-clockwise shift in the local magnetic field.— Dr Chris Smith, Naked Scientist
Listeners called in with other questions...
Why is there a marble or a ball inside the sprays used by graffiti artists?— Thabiso, caller
A lot of the sprays that we use in spray cans are based on a solvent which is used to suspend the particles of the paint explains the Naked Scientist.
He adds that the way the paints work is that you expel the paint mixed up in the solvent out of the tin, the solvent then evaporates and it leaves the paint sticking on the wall.
The paint and the solvent are two quite different chemicals and they separate inside the tin. So if you just press the button then you would end up with either all the paint or all the solvent, whichever is heaviest and at the bottom of the tin coming out first because of the straw that goes down inside the tin.— Dr Chris Smith, Naked Scientist
Listen to more questions and answers from the Naked Scientist in the clip below: