How something works Flashcards
A thermostat
A thermostat contains a strip or coil of steel and a strip or coil of copper, one on top of the other. As the strip / coil heats up, the metals expand, but one does it faster than the other. The strip / coil bends and connects with a switch, which turns off the power supply. When the strip / coil cools down, the metals contract and the switch is disconnected. The thermostat is adjusted using a dial or other control.
A disc player
A disc player (for example, in a computer) has several component parts. A disc is inserted into the player and begins to spin. At the same time, a thin beam of light called a laser strikes the disc and converts digital signals into sounds or images, which can be heard through speakers or viewed on a screen. Volume or brightness can be increased or decreased by means of a button, knob or other control. Nowadays, discs are largely being replaced by storage devices like memory sticks, which have no moving parts.
An aerosol
In an aerosol, liquid and gas are compressed in a metal and / or hard plastic tube. This can be released from the tube by pushing a button, which opens a valve. When the liquid–gas combination leaves the tube and mixes with oxygen, it rapidly expands.
An aircraft
Most aircraft are made of aluminium, and require two forces to allow them to fly: thrust and lift. As the aircraft moves forward on the ground under the power of its engines, air flows over the wings. As it accelerates / moves faster, creating / producing more thrust, a vacuum is created / formed over the wings. This creates / produces lift. The aircraft is pulled into the air by the force of this lift.
A digital camera
A digital camera consists of two main parts: a body and a lens. When a button is pressed on the body, a window in the lens called a shutter opens and light enters the camera. The amount of light going into the camera is controlled by both the speed of this shutter, and a smaller window called an aperture. Both the shutter speed and the size of the aperture can be adjusted by the person using the camera. The light hits a sensor in the body of the camera, which records the light as a digital image. The image is recorded / stored on a memory card in the camera, and this can later be
downloaded onto a computer.
Knob
Noun
A rounded lump or ball, especially at the end or on the surface of something; Handhold- Hand grip: Volume or brightness can be increased or decreased by means of a button, knob or other control
Aperture
Noun
An opening, hole, or gap; Orifice: The amount of light
going into the camera is controlled by both the speed of this shutter, and a smaller window called
an aperture.
