If you’ve ever been under a lot of stress or had a lot of energy to burn, you may have heard someone tell you that you need to “blow off steam.” You probably understand that they mean you should go do something that will help you get rid of that extra energy or stress, like exercising or spending the day at a place like Fort Edmonton Park. But where exactly does the expression come from?
Well, when you see a train travelling today it is probably powered by diesel fuel or even electricity. When the train first arrived in Edmonton in 1902 it would have been powered very differently “ with steam!
So how does a steam engine work? Well, there are several important components to a steam engine: we’ll start off with a part called the firebox, which (you guessed it!) is where the fire is located! The firebox burns coal to produce heat. The heat and smoke will move from the firebox into the boiler, which is basically a big water tank. The water inside will heat up and produce steam. This steam then travels through a cylinder which contains a part called a piston. The steam pushes the piston back and forth, which turns the wheels of the train and moves it forward.
Are you starting to guess how the phrase “blow off steam” came into being? The steam in the boiler can create a lot of pressure “ sometimes so much that if the engineers don’t do anything about it the boiler could explode! In order to avoid this boilers are built with a kind of safety valve called a “blow off valve” which releases the steam. If the pressure in the boiler becomes too great, the engineers can open these valves and “blow off steam” to release the pressure, kind of like what we need to do when pressure and stress start to build in our own lives!
If you’re interested, learn more about how steam engines work!
This post is part of a 6-part series called “Why do we say that?“