The objects on display at Summerlee tell us stories about the history of this area and its people, but we can also use these objects to learn about science too! This page shows the science behind some of Summerlee’s displays.
Cardowan Winding Engine
There are many steam engines around Summerlee, on trains, cranes other machinery. A steam engine uses energy from heat to create movement.
Coal, or another fuel, is burned in the furnace of the engine, and this creates heat. This heat is used to boil water, in the boiler, and turn it into steam. When liquid water is heated to 100 degrees centigrade it changes into a gas- steam. When the water becomes steam it increases in volume – it gets bigger! As the boiler doesn’t get bigger the steam begins to run out of space and tries to escape – this increases the pressure inside the boiler. The more steam the boiler creates, the higher the pressure. A steam engine can use that pressure to make things move.
In the winding engine the steam is forced through pipes into the piston and quickly fills the piston up. There is a rod inside the piston and as the steam fills the piston the rod is pushed out. The rod is attached to the wheel and as the rod moves forwards the wheel begins to turn. When the rod has reached as far as it can the steam is ejected from the piston and the rod is sucked back inside the piston, which keeps the wheel turning. Then more steam is forced into the piston and the whole process repeats- the rod moves in and out of the piston and the wheel keeps turning.
Electric Lamps
To mine coal or iron underground miners need to provide their own light. They often used oil lamps, or candles to light their way but these were dangerous because the flames could ignite flammable gasses which were sometimes found in mines. To stay safe miners need a light source which did not have a flame. The electric light bulb came into use in mines in the early 20th century – the light comes from a glowing wire and there is no flame, so they are much safer to use underground.
The first electric light bulbs were known as incandescent light bulbs. This means they make light from heat. They do this by having an electric current flow through a thin wire, called a filament. The filament is made of a metal such as tungsten, which does not conduct electricity very well; this is called resistance. The filament resists the electric current and that resistance turns the electrical energy into heat. The heat energy makes the filament glow and give off light. The filament is held inside a glass bulb and all the air is removed from inside the bulb. This means that the filament won’t burn, no matter how hot it becomes, because fire needs heat, fuel and oxygen. Without oxygen the filament won’t burn and just continues to glow.
We no longer use incandescent light bulbs because they use a lot of energy to make light. We use LED (light emitting diodes) today because they can make light without heat, which means they are cheaper and better for the environment.
Tropenas Convertor
Steel is iron which has had carbon added to it. Steel is stronger and lasts longer than iron as it is less likely to rust. Molten iron is poured into the converter and hot air is pumped in. The air allows any impurities in the iron to oxidise. These impurities will either become a gas which floats away, or will form another liquid, called slag, which floats on top of the molten iron and can be taken away. This leaves pure molten iron in the converter, to which is added the carbon to form steel.
Oxidation is when a substance combines with oxygen to form a new substance. Any time something burns in a fire it oxidises: it combines with the oxygen in the air. Burning the impurities in the molten iron inside the convertor means they create a new substance which is easily separated from the iron.
In the converter oxidation is caused by fire, or combustion. A fire requires three things; fuel, heat and oxygen; this is known as the fire triangle, because removing one of these things means the triangle will collapse. The impurities in the iron are the fuel and the heat is provided by the molten iron, which is heated before being poured in. To complete the triangle oxygen needs to be added and this is achieved by pumping hot air into the converter.