Most of our electricity still comes from power stations burning fossil fuels. They release a large amount of energy, from small amounts of fuel, and are relatively cheap. Fossil fuels are non-renewable and cause a large amount of pollution.
A nuclear reactor uses the energy released from splitting atoms, of uranium or other radioactive fuels, to produce steam to drive turbines. The process is called nuclear fission.
The compressed fluid, generated from ‘wave power’, turns hydraulic pumps, connected to electrical generators. The UK is currently seen as a world leader in the development of wave and tidal stream technologies.
Fleming's left-hand rule is used with electric motors to identify; The direction a coil of wire will move in a magnetic field, the direction of the magnetic field, or the direction of the current flowing through the wire coil.
An electric generator converts mechanical energy into electrical energy. They work by spinning a coil of wire inside a magnetic field. Using more turns of wire, or a stronger magnetic field gives a bigger current.
A circuit breaker does the same job as a fuse, but can easily be re-set. An electromagnet is used to break the circuit, if the current goes too high, and an external switch is used re-set the breaker.
The digestive system breaks down large food molecules (digestion) when they are small enough, they diffuse into the bloodstream, a process called absorption. Digestion can be separated into two processes: Physical and chemical.
The heart and blood vessels are a transport system. They carry digested food molecules, H2O and O2 to the cells and remove waste products like CO2. Humans have a ‘double, closed, circulatory system’.
We have three main types of muscle; Heart (Cardiac muscle) a very special type of muscle that never tires. Involuntary (Smooth muscle) organ muscle, we have no conscious control over this type, and Voluntary (Striated muscle) attached to bones to allow us to move.
The female reproductive system is made up from: The ovaries, that contain the undeveloped egg cells (gametes). The fallopian tubes, that transport the eggs. The womb (uterus) where the foetus develops. The cervix, a ring of muscle. The vagina, a muscular tube.
Reproductive cells, egg and sperm, are called gametes. Gametes are formed during a special type of cell division called meiosis. Body cells (except Red blood cells) all contain 46 chromosomes, 23 pairs, gamete cells only contain 23 chromosomes.
The kidneys contain millions of tiny tube-like structures, called nephrons, that filter the blood in a process called ‘Ultrafiltration’. The nephrons are formed from; The Bowman's capsule, convoluted tubules and the loop of Henle.