lunes, 25 de abril de 2011

Vocabulary 6 - Sources of energy

Solar cell: a device that generates an electric current from sunlight.


biomass conversion: getting energy from plant and animal materials by changing them into high-quality fuels.


nuclear fission: the splitting of nucleus with a large mass into two nuclei with smaller masses.


chain reaction: a reaction that is kept going by products of the reaction.


nuclear fusion: the merging of nuclei with smaller masses into a nucleos with a larger mass.



hydroelectricity: the use of flowing water to generate electricity.


thermal pollution: the excess heating of the enviroment.

Vocabular 5 - Temperature, Heat, And Matter.

Thermal expansion: the expansion of matter when its temperature is raised.


pressure: the force on each unit of area of a surface.


melting: the change of a solid into liquid.


vaporization: the change ofliquid to gas as molecules break free from each other.


Condensation: the change of gas into a liquid as molecules attract each other.


freezing: the change of a liquid into a solid.


boiling: the formationof bubbles of vapor that escape from a liquid that is being heated.


evaporation: the vaporization of molecules from the surface of a liquid.

Vocabulary 4 - Temperature and Heat

Kinetic energy: the energy of a moving object.


Pottential energy: energy stored in an object or material.


Temperature: the average kinetic energy of the molecules in a material.


Heat: energy that flows between pbjects that have different temperatures.


Radiation: the transfer of energy by electromagnetic waves.


Conduction: the transfer of energy byeby direct contact of molecules.


Convection: the transfer of energyby the flow of aa liquid or gas.


Insulation: prevents heat from flowingin or out of a material.

miércoles, 13 de abril de 2011

Vocabulary 3 - Chemical Change

Compound: a chemical combination  of two or more elements.


Chemical bond:  a link that atoms or electrically charged particles can form with each other.


Chemical formula: a way of using letters and numbers to show how much of each element is in a substance.


Ion: an electrically charged particle with unequal numbers of prtons and electrons.


Molecule: a group of bonded atoms that acts like a single patricle.


Chemical property: a way of describing how a substance changes chemically with other substances.


Exothermic: a reaction that give off heat.


Endothermic: a reaction that absorbs heat.

Vocabulary 2 - Elements and Atoms

Element: a substance that cannot be broken down any further into anything simpler.
Atom: the smallest particle of an element that has the same chemical properties as the elements.


Nucleus: an atom`s dense center, where most of it mass is.


Electron: a negatively charged particle that moves around an atom`s nucleos.


Proton: a positively charged particle inside an atom`s nucleus.


Neutron: a particle with no charge inside an atom`s nucleos.


Atomic Number: the number of protons in an atom.


Metal. any of a group of elements that conduct heat and electricity, is shiny and bendable.

sábado, 12 de marzo de 2011

Vocabulary 1 - Physical Properties

1. Matter: any solid, liquid or gas.

2. Mass: amount of matter in an object.


3. volume: the amount of space an object takes up.


4. Density: the amount of mass in a certain volume of material.

5. Physical Property: a property that can be observed without changing the the identidy of a substance.

6.  Physical Change: a change in size, shape, or state without forming a new substance.

7. Solution: a mixture of one substance dissolved in another so that the properties are the same throughout.

8. Chemical change: a change in matter that produce a new substance withh different properties of the original.