The simple answer here is because people get old. Not an answer that satisfies your average child though! It is all to do with pigment and cells. The hair is like a tube that is full of both and in-between are spaces. In young people this space is filled with a fluid and this has the job of keeping the cells and the pigments in their place. That means that young people keep their hair color really well because, let’s face it, they are full to brimming with fluids of one kind or another. As we get older we don’t produce as many - ahem - fluids and the space between the cells and the pigment is filled with air instead. This means that the pigment is gradually lost and the process of graying reflects that.

It’s all about sebum! This can produce hilarity among a group of ten year olds because they see bum everywhere and they love double entendres as much if not more than adults. Sebum is produced from the sebaceous gland (each hair has one at its, err, bottom) and it is pumped out to make a layer that stops Mr H20 getting in to our skin. It also keeps it bouncy and stretchy. However, we do not have any hairs on the palms of our hands - or for that matter the soles of our feet! The water can then get in to our skin and makes it wrinkly. The wrinkliness - rather than puffiness or swollenness - is caused because of the ridgy way the layers of our skin are joined together. A simple answer here might be simply because our palms aren’t waterproof!

It’s all to do with sympathy! Or rather it is when our sympathetic nervous system goes in to overdrive. This is a system of nerves that we have no control over whatsoever. The nerves become more active due to what we are experiencing in the real world. So, an ordinary encounter with a friend, someone we find attractive or a customer can turn out to be socially embarrassing due to no fault of our own! Another reason for blushing is a little simpler. When we experience heightened emotions it causes an increase of blood to the face. Blood is red and you know the rest of the story. The reason we don’t stay red - now that would be funny - is that our nervous system returns to normal after a short time.

Well, for a start, you can tell the inquiring infant terrible that the funny bone is, in truth, a nerve. It runs through a ridge in the bone really close to the inside of the skin. The proper name is the ulnar nerve and it is called this because its route is directly through the ulna, which is one of the bones on your forearm. It’s the bone on the outside - get them to give it a feel! The ulnar nerve is a very important nerve because it gives us the feelings we have in our hands.

When you stick people in the ribs with your elbow, they might tell you that your bones are very sharp! That is because the ulna sticks out. So, the ulnar nerve, being so close to the surface, is easy to bump. When the ulnar nerve is knocked it can be quite painful and pain can often cause people to laugh just as much as cry. This is why it is called the funny bone.

Most kids know that women’s nipples serve a purpose. They can question though, why on earth dad has them too. Until around the tenth to fifteenth week in the womb there is no evidential difference between male and female embryos. After this, the hormones kick in (strange that it is around the same time, but only in years, in children!) and if dad has passed on a Y chromosome then a boy begins to form. When the second chromosome is an X then the embryo will become a girl. Before the hormonal kick in, however, the nipples have already been produced. Once made, they cannot be dissolved back into the fluids in the womb! So, that’s why men have nipples because at some point (for a very short amount of time) everyone is a girl!

For the answer to this question we have to look inside the body to the kidneys. The kidneys are there to do two things - the first is to make sure that waste is filtered out of our blood. The second is to keep the amount of salt we have in our blood at the same level. So, when we take a leak the main stuff inside the urine is water, salt and the rubbish our body doesn’t need. The main substance that we don’t want from the cells in our bodies that we get rid of through our urine is ammonia. From blood it is the “hem” bit of the hemoglobin (Who put the “heem” in the hemoglobin?” as the old song goes!). This is called bilirubin and was discovered by a gentleman called William Rueben. That very poor joke aside, the ammonia and the billirubin get to the liver and are converted in to substances that are much less dangerous to us.

Urea comes from the ammonia and the bilirubin is converted to something called urobilogens. Salt, urea and water have no color. But! Urobilogens are yellow! So if you have had a lot of water to drink your urine will appear lighter. If you haven’t had much water to drink then your urine will appear yellow, getting darker and darker the more dehydrated you are. If this is too much information to take in, tell the kid it depends on the amount of bananas we eat.

Very fast. That’s 43 kilometers per hour, which is twenty seven miles an hour. This, of course, is only over short distances. At this point reflect that although the adult male can run at this speed for only a short amount of time a small version of an adult can ask questions ad infinitum. Then go try and figure out why.

Sometimes! The only parts of the ear that can continue to grow are the lobes. Most people will not experience this as once the head stops growing (although with some people it never seems to!) then so do the ears. The only organ of the human body that continues to grow throughout life is the nose - and this only a teensy weensy little bit. You could perhaps punish your offspring for their interminable biological questioning by telling them that their ears and nose will grow a millimeter a year for their whole life. That will stop them asking questions for a while as they ponder a Pinocchio like future!