Atoms and Nuclear Fission..
Large, heavy atoms (eg uranium) can become more stabe by losing an alpha or beta particle, a process whihc occurs naturally.
Stability can be gained more quickly by bombarding the nucleus of the atom of uranium with neutrons in a process called nuclear fission.
is the process of splitting atomic nuclei. It is used in nuclear reactors to produce energy to make electricity.
The products of collision are two smaller nuclei and two or three other neutrons along with the release of an enormous amount of energy.
A single neutron colliding with a 235U nucleus produces two further neutrons. These neutrons can go on to interact with further 235 U nuclei, producing four neutrons, then 8, 16, 32 and so on. Chain reaction is produced- when a fission reaction produces large amounts of energy.
Manipulating the chain reaction allows it to be used in two different ways...
Uncontrolled chain reaction
- neutrons bombard pure uranium nuclei
- an enormous amount of energy and radiation is released
- THIS FORMS AN ATOMIC BOND
Controlled Chain Reaction
- neutrons bombard a mixture of 235U and 238U nuclei
- the heat produced is used tomake steam to generate electricity
- THIS FORMS A NUCLEAR REACTOR
Nuclear infsion invovles the joining together of two or more atomic nuclei to form a larger atomic nucleus. It takes a huge amount of heat and energy to force the nuclei to fuse. This is not a practical way to generate power. Energy produced in Fusion is much greater that the energy produced in Fission.
A large amount of work is currently being done. Cold Fusion would occur at much lower temperatures.
Static electricity- electrical conductors- materials that allow electricty to flow through them easily. Insulators include plastics.
However it is possible for insulators to become electricaly charged if there is friction between it and another insulator. When this happend , electrons are transferred from one material to the other. The insulator is the charged with static electricity.
Repulsion and Attraction...
Electric charge builds up when electrons are rubbed off one material onto another. The material receiving electrons become negatively chated and the one giving up electrons becomes positively charged.
Two materials with the same type of charge repel each other, two materials with different types of chage attract each other.
EARTHING- Allows a constant safe discharge to occur to equalise the elcectron imbalance between the two objects. When earhing occurs, electrons flow from one body to the other to remove the imbalance.
Electrostatic- the stationary electric field that surrounds a charged obect; caused by friction.