When you sip soda through a straw, you are utilizing the simplest of all suction mechanisms. Sucking the soda up causes a pressure drop between the bottom of the straw and the top of the straw. With greater fluid pressure at the bottom than the top, the soda is pushed up to your mouth.
This is the same basic mechanism at work in a vacuum cleaner, though the execution is a bit more complicated. In this article, we'll look inside a vacuum cleaner to find out how it puts suction to work when cleaning up the dust and debris in your house. As we'll see, the standard vacuum cleaner design is exceedingly simple, but it relies on a host of physical principles to clean effectively.
It may look like a complicated machine, but the conventional vacuum cleaner is actually made up of only six essential components:
An Intake port, which may include a variety of cleaning accessories
An exhaust port
An electric motor
A porous bag
A housing that contains all the other components
When you plug the vacuum cleaner in and turn it on, this is what happens:
1. The electric current operates the motor. The motor is attached to the fan, which has angled blades (like an airplane propeller).
2. As the fan blades turn, they force air forward, toward the exhaust port (check out How Airplanes Work to find out what causes this).
3. When air particles are driven forward, the density of particles (and therefore the air pressure) increases in front of the fan and decreases behind the fan.