SIMPLY FACTS

1. Although plants do not have nerves, they do use electrical impulses for coordination.  These impulses are like the humans, but much slower.  The Venus flytrap plant is a good example.
2. A single photon of light – the smallest quantity you can get, is enough to stimulate a rod cell.
3. Each off your fingers has about 3000 touch receptors.  This is as many as the whole of your back and chest.
4. You can survive for weeks without food, but only a few days without water
5. A healthy man should have about 15% of his weight as body fat.  A healthy woman should have about 25 %.
6. Alcohol gets from the stomach to the brain in just few minutes.
7. The heat inside the Earth is produced when radioactive substances called isotopes decay. It is not heat left over from when the Earth first formed.
8. One strand of optical fibre can handle up to 10000 telephone conversations all at the same time.
9. The reason stars seem to twinkle is because the atmosphere distorts the light reaching our eyes.  Out in space stars give a steady, clear light.
10. Our sun is a middle-aged star. It is about 4600 million years old.  It burns about 4 million tonnes of hydrogen every second.
11. Comets come from deep space.  As they get closer to the Sun they develop a tail of dust and ionized gas.  The tail always points away from the sun, even when it moves away back into deep space.
12. Our sun and solar system are only 4.6 billion years old. That means that our part of the Universe has probably gone through the birth, life, and death cycle at least three times already.
13. Dark matter does not emit any electromagnetic radiation and therefore it cannot be seen by any of our telescopes.  It is thought that 85% of the Universe could be dark matter.
14. A drop of your blood contains about 5 million red blood cells.
15. During an average life a heart beats over 2 500 000 000 times and pumps 340 million liters of blood.
16. Bats can disconnect the bones in their ears while they send out their ultrasound squeaks, so that they don’t deafen themselves.