miércoles, 27 de abril de 2011

Temperature, heat, and matter

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


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


Melting: the change of solid into a liquid.


Vaporization: the change of a liquid to a gas as molecules break free from each other.


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


Freezing: the change of a solid into a liquid.


Boiling: the formation of bubbles of vapor the escape from a liquid that is being heated.
Evaporation: the vaporization of molecules from the surface of a liquid.

jueves, 7 de abril de 2011

Tempeture and Heat

Kenetic energy:The energy of a movning object.



Potential energy:Energy stored in an object or materials.



Tempeture:The average kinetic energy of the molecules in a material.



Heat:Energy that flows between objects that have different temperature.


Rdiation:The transfer of energy by electromacnetic waves.
Coduction:The transfer of energy by the flow of a liquid or gas energy by direct contact of molecules.
Convection:The transfer of energy by the flow of a liquid or gas.



Insulation:Prevents heat from flowing in or out of a material.

sábado, 2 de abril de 2011

Chemical Changes

Compound:A chemical combination of 2 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 substances.

Ion:An elecrtically charged particle with unequal numbers of protons and electrons.

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

Chemical property:A way of describing how a substances change chemically with other substances.


Exothermic:A reaction that gives off heat.


Endothermic:A reaction that absorbs heat.

domingo, 20 de marzo de 2011

Element and atom

Element:a substancesthat cannot be broken down any further into anything simpler.


Atom:the smallest particle of an element that has the same chemical properties as the element.


Nucleus:an atom´s dense center, wheremost og its mass is.
Electron: a negatively charged particle that moves around an atom´´s nucleus.
Proton: a positively changed particle inside an atom´s nuecleus.
Neutron:a particle with no charged inside an atom´s nucleus.


Atomic numbers: the number of protons in an atom.


Metal:any of a group of element that conduct heat and electricity, is shine and bendable.

sábado, 19 de marzo de 2011

Physical properties

Matter:any solid liquid or gas.


Mass:amount of matter inan object.


Volume:the amount of space and object takes up.


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


Physical Properties:a property that can be observed without changing the identify of a substances.


Physical Change:a change in size, shape, or state withoutforming a new substance.


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


Chemicl Change:a change in matter that produces a new substances with different properties from the original.