![]() Steam engines basically run by boiling water and you must deal with impurities because, if the water foams, it starts to affect how the machine works. ‘The railways very swiftly employed metallurgists to figure out how long rails would last,’ Bob says, ‘and then they quickly went on to do other things, too. By 1864, less than eight years after the Bessemer process was discovered to mass-produce steel, the London and North Western Railway company employed a chemist to make improvements.īy the 1960s, chemistry had become so integral to the rail network that it accounted for more than half the staff at the UK’s Railway Technical Centre in Derby The wooden wheels soon evolved into wrought iron but, Bob says, they could very easily shatter, so steel became a priority for early railways – and with it came chemistry. ‘Railways go back to at least 1604 in the UK, when Huntingdon Beaumont built a wagonway with wooden wheels and wooden rails in Nottingham,’ explains Bob Gwynne, assistant curator at the National Railway Museum in York. But the railway network wasn’t built overnight and science has always been at the heart of its development. Like I said, I'm not going to build a demonstration version of a railgun.The UK’s rail network is a modern colossus, made up of almost 10,000 miles of track and more than 2500 stations, with passengers completing around 41.5 billion miles of journeys every year. But wait! If I have 1000 amps in the rails, won't the rails also push on each other? Yes. Really, the only way to get that high of a current is with some type of capacitor bank that can be discharged very quickly. What about 1000 amps? Yes, that might do it. ![]() Also, there is no way my power supply could get up to 100 Amps. This would increase the force to just 4 x 10 -3 N. What if I increased the current? Actually, since both the force and the magnetic field are proportional to the current, doubling the current would increase the force by a factor of 4. Since the magnetic field and the current are perpendicular, this is easy to calculate the magnitude of the force. Now if I have the same 10 amp current running through the 2 cm long cross over wire (projectile), I can use the following to calculate the force on a wire with current: If I use a distance of 2 cm and a current of 10 amps, I get a magnetic field of 2 x 10 -4 Tesla.~ r is the distance from the center of the wire. Maybe this diagram will help visualize what's going on. This magnetic field then pushes on the projectile with the current running through it to propel it out of the railgun. In between the two parallel rails, both of the magnetic fields due to the rails points in the same direction and make a stronger magnetic field. An electric current goes down one wire, across the projectile and then back down the other rail. You have two parallel rails (thus called a railgun) and a moveable projectile that is also like a wire. Putting these two ideas together, you can make a railgun. One direction is in the direction the wire swings. There are only two directions perpendicular to both of these vectors. In this example (from the video), the current is to the left and the magnetic field is upwards. What about the direction of the force? This force is perpendicular to both the direction of the current and the direction of the magnetic field. When current runs through the wire, there is a magnetic force on the wire which causes it to swing. The wire with current is near the magnet. Don't keep the wire on the battery for too long, it will get hot. How much it moves depends on how much electric current is running through the wire (and how close the needle is to the wire). When you connect this wire to a battery, you will see the magnetic compass needle below the wire move a little bit. Next take a wire (any conducting wire should probably work) and place the wire such that it is oriented along a North-South line over the compass. Well, you might not have a magnetic compass - but you should get one anyway (your phone won't work in a zombie apocalypse). You probably have the materials so that you can try this at home. Let's go over some of the basic principles for the railgun to operate. What about a railgun? This weapon can fire a projectile at tremendous speeds without even using an expanding gas. The shell is then launched by the expansion of exploding gun powder. ![]() ![]() A conventional cannon has some type of shell in a tube. ![]()
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