A fire truck pulls up to the scene. The fire fighters jump out and quickly attach the hose to the truck. In the meantime another set are either attaching a hose from the truck to another water truck or to the fire hydrant nearby. Once all is locked and ready the fire fighter holding the end of the hose turns the nozzle and lets it loose on the burning house. The water comes gushing out at high pressure towards the flames dancing amidst the black scarred walls of the house. As the water hits the flames there is a hissing sound and then steam rises in the air. Check out modern farm implements for sale to find out other products and services offered.
This is a scene that none of us hope to ever see, whether it be your home, that of a friend or even a stranger. No one wants to see the livelihood or place of abode disappearing in flames. At the time this is happening though a marvellous bit of science is taking place to assist in dissipating the flames. The way the water rushes from the hose at seems to fly a great distance from the hose to the flames is truly astounding. Once you get past the fact that a house is burning down, of course. Just what makes the water leave the fire fighting hoses at such high speed?
Well, it is something we call pressure. Pressure in general terms is any kind of force exerted on one body by another. So when you put your hands on your door and push to close it, you are applying pressure to the door to close it. The word pressure is normally used in terms of fluids however, and so it would be best to think of pressure being synonymous with liquids like water.
If you have ever been to a pool and tried to go to the bottom of the pool and sit on the floor you will feel a strange tingling in your ears. You will also feel this same feeling when you are in an airplane and it is either ascending or descending. In both these cases it is due to a change in pressure of the surrounding fluid that you feel this strange sensation in your ear drums.
So back to the hoses attached to the fire truck. In that case pressure is created inside the hose by forcing the fluid, which is the water, through a small space. As the weight of water is forced to go through this bottleneck the water has to increase speed to allow more to go through the small space. As a result of the increased speed created by the pressure of the water you get water gushing out of the fire hose. That is the science that the fire fighters depend on to get fires out.