How does a mobile phone mast work? What affect does living in space have on the human body? Could tractor beams become a reality? We take on these space age questions in this week's show as well as reveal the land area of Earth, why people in the Southern Hemisphere don't walk on their heads, why hair looks darker when wet and why alcohol makes you feel happy. Plus, we investigate what would happen if we drilled to the centre of the Earth! Like this podcast? Please help us by supporting the Naked Scientists

Are we at risk when we use public toilets? What can we catch from kissing strangers? Why is it safer to eat cooked rather than rare meat? We take on these risk averse questions as well as find out how the sun burns, why children shouldn't drink coffee, the direction our blood flows around our body and how much ruminent animals and permafrost contribute to our greenhouse gases. Plus, we investigate whether it's more efficient to run our cars on a half or full tank of gas! Like this podcast? Please help us by supporting the Naked Scientists

Why do Pigeons nod their heads? How does food become body fat? What can you do with a ramjet? We take on these questions as well as discover how megapixels are formed, whether bees go into their hives at night and why we use CO2 in fizzy drinks. Plus, we sniff out why cows produce methane! Like this podcast? Please help us by supporting the Naked Scientists

On Ask the Naked Scientists this week, we find out how cacti can survive with very little water, and why they are so well endowed with spines! We answer your questions on asteroids, the size of the universe and the correct angle to leave the Earth. Plus, we test Dave's knowledge of anti-ageing cosmetics! Like this podcast? Please help us by supporting the Naked Scientists

How did we measure geographic distances before GPS? And how do GPS satellites do it now? Would floating bridges help in Pakistan? We'll tackle all of these questions this week, as well as finding out if ice would melt in space and ifall the alcohol evaporates if you use it in cooking. Plus, whether explosions in space just keep going... Like this podcast? Please help us by supporting the Naked Scientists

How small is a proton? What is a photon? And how do colour-changing toys work? We'll find out the answers to all these questions this week, plus find out how new stars are born, how painkillers work and the effects of salt on our bodies! Like this podcast? Please help us by supporting the Naked Scientists

How do lasers work? Could lasers be used to treat cataracts and blindness as well as our eyesight? Why is a hydrogen atom bigger than a helium one? Why is there no oxygen on other planets? We take on these questions in this week's show as well as find out whether South American Indians can really shrink heads, whether microwaves could be altered to cool food down, if women will survuve longer than men on earth and investigate if it's possible to make artificial gravity out in space! Like this podcast? Please help us by supporting the Naked Scientists

Why does time seem to go by faster as we get older? What do IQ tests really measure? How do probiotic yoghurts work? We get the answers to all these on this week's show, as well as finding out why hair goes lighter in the sun and how 3D televisions work. Plus, is there such a thing as a 'good' virus? Like this podcast? Please help us by supporting the Naked Scientists

Why does sugar look so different when you heat it up? How much CO2 is there in all the world's bottles of Cola? And which way is it to the Centre of the Universe? We'll tackle all these questions this week, as well as discovering what causes thunderstorms, and whether aeroplanes would work in space. Plus, does wrapping your fish and chips in newspaper make it poisonous? Like this podcast? Please help us by supporting the Naked Scientists

Do we really need 8 glasses of water a day? How does a jet engine work? Where does earwax come from? Why are some apes vegetarian when we're not? We find out the answers to all these questions, as well as discover what thunderflies are, investigate if we're any closer to a malaria vaccine and discuss why bird feathers are so colourful. Plus, we find out about a newly discovered chemical that promotes cell survival in our brains! Like this podcast? Please help us by supporting the Naked Scientists