Most of the cells in your body aren’t yours.

Strange but true. Despite everything we do in modern Western culture to avoid germs, we are nonetheless walking germ incubators, hosting bacterial infestations from the skin to the deepest parts of the gut. Studies suggest there are ten times as many microbe cells in your body as cells that have your own DNA (thankfully bacteria are small compared to human cells and so don’t take up as much space). Bad though that might sound, overall it’s actually a very good thing. For instance bacteria produce chemicals that help you harness energy and nutrients from your food. And around forty human genes appear to have come from bacteria. Having “good” bacteria on your skin can also stop more harmful varieties from getting a foothold. For children, early exposure to bacteria is a vital part of building a healthy immune system.

Why tiny “paper cuts” hurt so much.

It isn’t only paper cuts which seem to bring pain disproportionate to their size. Any shallow cut or other wound which is not sealed off, such as an ulcer or a burn, will probably hurt more than a deeper one. The main cause of the extra pain from shallow cuts is in fact a lack of blood. Because a shallow cut doesn’t bleed very much, the pain receptors are left open to the air, ensuring continued pain. Paper cuts also cause surprisingly acute pain since they usually involve a large number of skin surface pain receptors in a small area of the skin. The fibres from paper and chemicals present in it, such as bleach, can also cause extra irritation. Additionally, paper cuts normally occur in the fingers, which just happen to be where you have the greatest concentration of sensory receptors. A paper cut on your thigh for example wouldn’t hurt nearly as bad because the thigh doesn’t get nearly as much attention from your brain when it comes to feeling pain.

What makes the sky and sea blue?

A cloudless sky is blue because of the way the light from the sun is affected by the molecules which make up the air. As the sunlight enters the atmosphere, part of it is bent or scattered. However the air scatters blue light much more than other colours. Because that scattering happens in all directions, the light hitting your eyes is mostly the scattered blue light, which makes the sky appear blue overall. The same effect makes the sunset red and orange. When the sun is at the angle where sunsets are visible, the blue light is being scattered away from your line of sight, leaving the red and orange colours to predominate.

The colour of the sea is even simpler – the sea reflects the sky, sending back to your eye the light that hits it, which is blue on a clear day. On a cloudy day it won’t look very blue at all.

What’s the worlds hottest chili and are super hot chilies ever hot enough to be dangerous?

Capsaicin and related chemicals, collectively known as capsaicinoids, are what make chili peppers hot. When you eat capsaicinoids they bind to the pain receptors in your mouth and throat that normally sense heat. These receptors then send a message to your brain that you’ve eaten something hot. Chili pepper heat is measured in Scoville units. The mildest peppers have a score of zero units, jalapeños three to six thousand units, and habaneros three hundred thousand units. However the Guinness Book of records says the hottest chili pepper is the Naga Jolokia, which grows in Northwest India and measures over 1 million Scoville units. Wildlife experts use smoke bombs made from this monstrous chilli to keep elephants away. For academic interest, pure capsiacin measures 16 million Scoville units.

Can a chili pepper ever be hot enough to harm you? Peppers are rich in Vitamin C and are believed to have many health benefits. Laboratory research has associated chilies with positive effects on cancer, weight loss, cholesterol, diabetes, ulcers, pain relief and microbial contamination of food. On the other hand even a small amount of a hot chili may temporarily aggravate haemorrhoids and existing joint pain conditions. But the overall answer is that trying to eat super fiery chillies isn’t going to harm much more than your ego. Anyone with a cast iron stomach can get their hands on some insanely hot chili sauces here

Can lead be turned to gold?

Before chemistry evolved as a science, alchemy ruled the roost. One of the most famous quests in alchemy was to discover a method to transmute lead into gold. Needless to say, over the centuries alchemists didn’t manage to achieve this. So is it impossible to turn lead into gold? Both lead and gold are defined by the number of protons (subatomic particles) they possess. All you need to do to change lead into gold therefore is to remove three protons from the lead atoms. Unfortunately this can’t be done by any chemical means. Physics on the other hand can be used to add or remove protons, but because lead is stable, making it release protons requires vast amounts of energy, such that the cost of transmuting it greatly surpasses the value of the resulting gold. So theoretically lead can be turned into gold.

Transmutation of lead into gold isn’t just theoretically possible though – it appears to have been achieved! Glenn Seaborg, the 1951 Nobel Laureate in Chemistry, is said to have succeeded in transmuting a small quantity of lead into gold. And in 1972 Soviet physicists at a nuclear research facility near Lake Baikal in Siberia reported that they had accidentally discovered a reaction which turned the lead shielding of an experimental reactor to gold. Although presumably highly irradiated gold is not very valuable.

Can paper be recycled over and over indefinitely?

Paper products make up as much as 23% of household rubbish. So finding a way to reuse that waste is a no-brainer for meaningful recycling. As well as saving trees, recycled paper uses half the energy and less than half the water of new paper from virgin wood pulp. Recycling a ton of paper can save seventeen trees, three hundred and eighty gallons of oil, three cubic yards of landfill space, four thousand kilowatts of energy and seven thousand gallons of water However, although recycling makes very good sense, paper can’t be recycled indefinitely. Every time a fibre is recycled, it loses some of its strength and after being reused several times, it’s no longer useful for papermaking. A typical piece of office grade paper can be recycled a mere seven times.

A tiger keeps its stripes even if you remove its fur.

The purpose of tiger stripes is to create a disruptive camouflage. The stripes break up the animal’s outline, especially in long grass. They also draw the eye away from the tiger’s shape, which prey would normally react to. Tiger stripes are unique to individual tigers like human fingerprints are to us and no two tigers ever carry the same pattern. However a tiger losing its fur can rest easy. The stripe pattern is found on the tiger’s skin, so even if you were able to give one an all over shave, its distinctive camouflage pattern would be preserved. Your house cat’s fur markings are also skin deep, although please don’t attempt to shave it to prove this for yourself!

Does your skin change every seven years?

Most human cells are much younger than the person in which they are found and very few of your cells will live as long as you do. One study found the average age of intestinal tissue is about eleven years, skeletal muscle tissue about fifteen years and brain tissues are up to ten years younger than you are. Jonas Frisen a stem cell biologist at the Karolinska Institute in Stockholm has suggested that the average age of the cells in an adult human may be seven to ten years. The epidermis, or skin surface, is amongst the youngest part of your body, being recycled every two weeks or so. A reason for the quick replacement of skin is that since it’s your body’s exposed frontline, it’s most prone to wear and tear

Can a breakfast bagel falsely mark you as a drug abuser?

Possibly if it’s coated with poppy seeds. The little black poppy seeds on baked goods are from the same plant used for opium production. The ripe poppy seeds you eat don’t contain narcotics but they do contain the same chemical indicators drugs tests are looking for. A false positive in a test can occur as long as 48 hours after eating poppy seed baked goods. Nor do you necessarily need to eat a huge amount of poppy seed bakery products to test positive. The website poppies.org has reported that during a test, a volunteer who ate one poppy seed bagel showed a level just under the U.S. Department of Health and Human Services’ guideline for a positive test. The experiment was conducted because a person who tested positive claimed to have eaten two poppy seed bagels for breakfast, and had results consistent with that. So you could test positive for opiates on urine based drug test by eating just two poppy seed bagels (or muffins) for breakfast.

The Snopes website verifies several cases where police officers and others have been fired due to false positive tests. Snopes also points out that the US Federal Bureau of Prisons makes inmates on furlough agree not to eat any poppy seeds.

What’s the world’s most dangerous animal?

Lion, tiger, venomous snake, shark? It’s probably not what you’re thinking. The biggest mass killer of humans is: the humble mosquito, which is responsible for over two million deaths a year through spreading malaria. Surprisingly elephants and bees kill more people than lions and jellyfish more than sharks. You can see the top ten killers here