Physics Facts & Trivia A rubber band shrinks when heated and expands when cooled because of the change in its Entropy state. Due to the effect of Thermal Expansion, the Eiffel Tower is upto 15cm taller in summer. Radar is an abbreviation ofRadio Detection And Ranging. If an atom were the size of a stadium, its electrons would be as small as bees. Laser is an abbreviation ofLight Amplification byStimulated Emission ofRadiation. Light does not age. At 25, Physicist Lawrence Bragg is the youngest person to receive a Nobel Prize. Atom is over 99.9% empty space. The most powerful lasers are made with Neodymium-doped Yttrium crystals. In a fraction of a second, they produce more power than the whole United States. Sunlight exerts pressure (solar radiation pressure). The effect of Relativity made Astronaut Sergei Avdeyev a fraction of a second younger upon his return to Earth after 747 days in space. The Dead Sea is so dense with salt, you can easily float on it without drowning. Lake Baikal in Russia contains more water than all the North American Great Lakes combined. The world's densest wood, theBlack Ironwood (Olea laurifolia), does not float on water and therefore sinks. The mass of our entire atmosphere is estimated to be some 5.5 quadrillion tons (55 followed by 14 zeros). The diameter of a proton is approximately 0.000000000001mm (1/25,000,000,000,000in). The amount of water beneath our ground soil is 50 times as much as all the water in the rivers and lakes combined. The first ten feet of the ocean hold as much heat as the Earth's entire atmosphere. The lightning bolt is 3 times hotter than the Sun. On average, our bodies constantly resist an atmospheric pressure of about 1kg per square cm.  The deepest location on Earth is Mariana Trench, about 11km deep in the North Pacific ocean. The bark of the redwood tree is fireproof. If Mount Everest were placed at the bottom of the deepest part of the ocean, its peak would still be a mile underwater. If given the same mass, our body would actually be hotter than the Sun. Many physicists believewormholes (a "shortcut" through space and time) exist all around us but they are smaller than atoms. A solar panel 100 miles by 100 miles (161x161km) in theMojave Desert (USA) could replace all the coal now burned to generate electricity in the entire U.S. The Atlantic Ocean grows at about the same rate as your fingernails. If you yelled for 8 years, 7 months and 6 days, you would have produced just enoughsound energy to heat up one cup of coffee. The average ice berg weighs 20,000,000 tons. Lightning strikes about 6,000 times per minute on our planet. A gallon of water weighs 3.8kg (8.34lb). If an item moves very, very fast, it becomessmaller and heavier. Minus 40 degrees Celsius is exactly the same temperature as minus 40 degrees Fahrenheit. The only rock that floats in water is pumice. Mexico City is sinking at a rate of 46cm (18in) per year as a result of draining water. 25mm (1in) of rain water is equivalent to381mm (15in) of dry, powdery snow. The oldest and largest clearly visible meteorite crater site in the world is The Vredefort Dome in Free State, South Africa. It is 380km across. The greatest tide change on earth occurs in the Bay of Fundy. The difference between low tide and high tide can be as great as 16.6m (54ft). The temperature in fahrenheit can be determined by counting the number of cricket chirps in 14 seconds and adding 40. The average ocean floor is about 3,600m deep (12000ft). Sunlight can penetrate clean ocean water to a depth of 73m (240ft) The North Atlantic gets 2.5cm (1in) wider every year. Hawaii is moving toward Japan 10cm (4in) every year. Due to gravitational effects, you weigh slightly less when the Moon is directly overhead. Lake Baikal is the deepest lake in the world. When hydrogen burns in the air, water is formed. Diamonds are the hardest known substance. Most gemstones contain several elements, except diamond which is all carbon. When glass breaks, the cracks move at speeds of more than 4,500km/h (3,000mi). If you could throw a snowball fast enough, it would totally vaporize when it hit a brick wall. On a clear day, a beam of sunlight can be reflected off a mirror and seen up to 40km away.