6th grade science
Terms
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- A change in which one or more new substances form. (rusting of a nail)
- chemical change
- A particle made up of 2 or more atoms, which may be alike or different
- molecule
-
A change in which the size, shape, or state of matter changes but no new substances are formed.
(freezing water or cutting an apple in half) - physical change
- An element that releases energy and tiny particles from the nuclei of its atoms.
- radioactive element
- The change of state from a solid to a liquid
- melting
- The process by which liquid water changes to water vapor.
- evaporation
- The process of a gas changing to a liquid.
- condensation
- French physicist Antoine Henri Becquerel discovers that the element uranium releases invisible energy.
- 1896
- Marie and Pierre Curie discover 2 new radioactive elements, polonium & radium.
- 1898
- Enrico Fermi, physicist, finds a way to control the release of nuclear energy.
- 1942
- Nuclear energy is used in more & more tools for detecting and treating disease (cancer); used for killing bacteria in food, controlling insect pests, and making smoke detectors.
- 1990's
- Several nations sign an agreement that forbids the giving or selling of nuclear weapons to countries that don't already have them. The agreement also forbids countries without such weapons to make them.
- 1970
- 1st nuclear power plant begins producing electricity in England
- 1956
- 1st ship powered by nuclear energy is launched. U.S. Navy submarine, Nautilus
- 1954
- first nuclear bomb test takes place in U.S.
- 1945