Knowledge N Fact4u

Why do car tires protect you from lightning strikes ? •Car tires do not protect you from lightning strikes. Although the rubber in a tire acts as an insulator at low voltages, the voltage in a lighting bolt is far too high to be stopped by tires or air.  •No matter how thick your tires are, they don't stop lightning, according to scientists. •A study states that inside a car can be a safe place to wait out a lighting storm, but it's not because any materials are blocking the lightning. •Rather, if the car is struck by lightning, its metal frame redirects the electrical current around the sides of the car and into the ground without touching the interior contents.  •The ability of a hollow conducting object to protect its interior from electrical fields and currents is one of the fundamental principles of electromagnetics.  •Such an object is called a Faraday cage. For this reason, riding around in a convertible, on a motorbike or on a bicycle duri...

How do tractor beams work ? •Up until recently, tractor beams (beams of light that tow objects) existed only in the world of science fiction. •While large-scale tractor beams that can tow space ships are still machines of the future, microscopic tractor beams are here today.  •The idea at first seams to defy physics. Shoot light at an object and the light's momentum should push the object away from the light source according to the law of conservation of momentum; not pull it closer like a tractor dragging its cargo. •But what if you managed to create a situation where upon striking the object, the light gains forward momentum instead of losing it.  •In that case, the law of conservation of momentum tells us that the object will lose momentum in the forward direction, even to the point of going backwards, towards the light source. •So there is a way to make a tractor beam without violating any physics, if you can get the light to ga...