| A | B |
|---|
| alpha decay | one of the 3 types of radioactive decay a radioactive atom will undergo to become stable. An alpha particle consists of 2 protons and 2 neutrons (Helium nucleus); this form of radiation is the least harmful to living things. |
| beta decay | one of the 3 types of radioactive decay a radioactive atom will undergo to become stable. Beta decay occurs when a neutron transforms into a proton and an electron. The proton remains in the nucleus but the electron is emitted |
| diffraction | the bending of a wave around an obstacle |
| Direct current | An electrical current traveling in one direction; battery |
| electrical conductivity | The property of a material that allows charge to flow |
| gamma decay | Same as gamma rays; one of the 3 types of radioactive decay a radioactive atom will undergo to become stable. Gamma decay has no particle associated with it, simply high energy electromagnetic radiation |
| half-life | length of time for half of a radioactive substance to become stable |
| isotope | An atom with a different number of neutrons, thus changing the mass number |
| nuclear fission | a nuclear reaction in which an unstable nucleus splits into two or more smaller nuclei while releasing a huge amount of energy (consistent with E=mc2) |
| nuclear fusion | a nuclear reaction in which nuclei combine to form more massive nucei with a release of huge amounts of energy. (2 nuclei fuse together to form a larger atom) |
| photon | a particle of light (electromagnetic radiation); a quantum of light energy |
| Radioactive decay | a process occuring in unstable nuclei to form a more stable nucleus; 3 forms - alpha, beta and gamma decay |
| friction | A force that resists the relative motion or tendency to such motion of two bodies in contact |
| Newtons first law | an object will stay at rest unless acted upon an unbalance force or an object will take in motion unless acted unpon on an unbalance force |
| Newtons second law | F=MA |
| Newtons third law | for every action there is an an equal and opposite reaction |
| refraction | The turning or bending of any wave, such as a light or sound wave, when it passes from one medium into another of different density. |
| reflection | a wave that bounces off a surface |
| alternate current | current that can change direction |
| direct current | current that flows in one direction |
