What keeps the Earth's core so hot?

What keeps the Earth's core so hot?

It's a combination of things. One, the earth's quite a big planet relative to Mars which is a bit smaller. There was a lot of heat that was in the Earth to start with. When the planets were first forming around the sun in what's called a protoplanetary disc a lot of the swirling and spinning material was crammed together and squeezed together. It had a lot of heat from that, those frictional effects. Also the Earth has what's loosely termed as radioactive compounds in the Earth. As these radioactive compounds break down and decay they produce heat. The heat is obviously concentrated in the core of the Earth and then filters up towards the surface. Because the Earth's a big planet it's got a big core. It's got lots of radioactive decay going on. Some of the heat that we're seeing is because the Earth is sustaining it's own heat by radioactive decay.

How can we tell what noises the dinosaurs make ?

How can we tell what noises the dinosaurs make ?

The reason you hear those sounds on TV is to make it more interesting. We know dinosaurs probably made noises because they had very good sense of hearing. If you look at dinosaur fossil skulls, you can trace their ear canals and work out where their ears would have been and the kinds of sound they would have responded to. If they could hear sounds, they could probably make sounds. In the late 90's scientists put a fossil through a CT scanner to look at the bone structure. The headpiece was a series of intricately connected tubes a bit like organ pipes. They analysed the structure of these canals and airways, and used a computer to model what would happen if air were blown past. They found that the dinosaur could probably have produced low pitched rumbling noises that could have carried a long way. So what we use for dinosaur sounds on TV is what can be inferred from studying the shape of their fossilised remains, with a bit of artistic license thrown in.

Why do mints make your breath feel cold ?

Why do mints make your breath feel cold ?

According to a group of scientists in San Francisco, the reason is that the same nerve fibres that signal hot and cold are also sensitive to menthol, an ingredient in mints. Normally when the temperature changes it causes pores on the surface of the nerve cell to open and close, changing the electrical activity of the cell, which the brain interprets as a change in temperature. But menthol can also affect the function of the pores in the same way and triggers the nerve cell into thinking that the temperature is lower than it is.

Who is sweatier, men or women ?

Who is sweatier, men or women ?

Men are definitely sweatier than women. Previously this was put down to the larger male stature, but a team of scientists at University of Dortmund, Germany, led by Barbara Griefahn, say different. In their laboratory they have set up a mock 'sweltering car'. 'Volunteers' sit for up to 2 hours under heat lamps, mimicking the effect of the sun beating down through the windscreen. Under these conditions men lose about 250 mls of sweat per hour during the experiment, 70 mls an hour more than female volunteers. This makes them officially sweatier, even allowing for size and weight, say the scientists.

Is it normal for you to have a body temperature lower than 36.7celsius ?

Is it normal for you to have a body temperature lower than 36.7celsius ?

Normal body temperature is 37?C. This is set by part of your nervous system and the hypothalamus, which is found in the brain stem. The hypothalamus monitors your body temperature and changes it if it becomes too hot or too cold. Your body temperature doesn't have to be exactly 37?C: exercise can make you hotter, while going outside on an icy day can make you cooler. The place in which you measure your temperature is very important. Putting a thermometer under your armpit will show you your peripheral temperature, and this can be quite a bit lower than your 'real' body temperature called your core temperature, or the temperature at the centre of your body. This varies very little at all in day to day life. It can best be measured by putting a thermometer in your bottom! You have to get very cold to change your core temperature, such as being stuck in freezing weather for a long time. People who have a drop in core body temperature have what is known as hypothermia. This makes them drowsy, and if left untreated, they will eventually become unconscious. When the body is cold, the chemical reactions that provide your cells with energy don't work as well. This makes cells function abnormally and, if prolonged, can be fatal.

Does the nicotine vaccine stop the cravings to smoke?

Does the nicotine vaccine stop the cravings to smoke?

Probably not. The mechanism works by stopping the effects, and so might actually increase the cravings. The vaccine is probably best used in combination with something that helps with the withdrawal symptoms. However, by stopping the effects, it also helps to break the cycle of reinforcement. Eventually this may lead to people stopping people smoking because it does nothing to help the cravings.

Which bacteria or viruses cause ear infections ?

Which bacteria or viruses cause ear infections?

The ears have the same linings and are connected to the nose and throat through the eustacian tube. This means that any of the viruses that cause colds and sore throats can get through into your ears. Viruses are the main invaders, but bacteria can cause secondary infection. They seize the opportunity to invade after a virus has caused the initial problem - such as damaging the protective lining of the airway, or blocking up the eustacian tubes in your ears with mucus.

What causes narcolepsy?

What causes narcolepsy?

Narcolepsy is the disorder where people fall asleep repeatedly during the day and there seems to be genetic component to this. Luckily there are drugs which can be used to treat it. There can be frightening aspects to narcolepsy, for instance people have been known to suddenly fall down as they fall asleep, or have nasty hallucinations as they fall asleep. The brain chemistry behind it is better understood now, and we do know about the genes that are linked to this. One particular chemical is a substance called hypocretin, and people with narcolepsy tend to have problems with the receptors for this brain chemical, or an abnormal form of this chemical. There are also people with 'clock' genes that give them a faster or slower body clock, but this shouldn't be mistaken for narcolepsy.

Would someone with a psychiatric disorder be better able to pass a lie detector test as they may not feel remorse?

Would someone with a psychiatric disorder be better able to pass a lie detector test as they may not feel remorse?

Old-fashioned lie detectors like the polygraph only detect stress. If the lack of remorse meant that the interviewees had reduced stress levels that would help them pass. Our lie detector, Silent Talker, makes its judgement on non-verbal behaviour: crudely what people call body language. Silent Talker can detect stress but lying involves other factors. We can only juggle a certain number of mental variables at once while we’re thinking. If we’ve got to try and maintain a whole load of different factors about an imaginary story it’s very difficult to do all the mental processing to keep that consistent. That’s what’s known as having a high cognitive load which affects non-verbal behaviour. Also duping delight occurs when liars get a kick out of getting a lie across successfully and again this affects non-verbal behaviour. In one of our own experiments on the general population we taught silent talk to recognise guilty feelings the participants felt while they were lying. When we added this information to the general lie detection we got more accurate classifications. In another independent study conducted by a different university using Silent Talker it was found that Silent Talker was effective at detecting lies told by psychopaths in interviews. So there we have it: evidence that remorse is a factor in the general population but also evidence that in the case of one disorder it’s not the only factor.

Why do we laugh when we find something funny?

Why do we laugh when we find something funny?

Something that’s funny is by definition something that makes us laugh. I’ll talk about why we laugh. Laughter is really a social phenomenon. If we look back to its origins, laughter, the ‘ha ha’ originated in the ‘pant pant’ of rough and tumble play such as you would find in tickle or the rough and tumble play of children. ‘Pant pant’ became the human ‘ha ha.’ With adults, however the arena of laughter has shifted from tickle and rough and tumble to a more linguistic and cognitive arena whereby, for example, the play of adults has to do with wordplay during conversations. You don’t have to tickle one of your colleagues to get them to laugh. You can tell them the joke. Even within conversation the key to laughter is the presence of another person. Laughter almost totally disappears when we’re alone. The key element for producing laughter is another person and not a joke. In fact we have followed people around and recorded what was said before people laugh. In only 10 or 15% is it anything remotely joke-like. Most laughter follows comments like ‘hey, where have you been? Ha ha!’ or ‘I’ve gotta go now, haha!’ These aren’t jokes so it basically is about developing bonds and relationships with other people.