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jueves, 19 de agosto de 2010

What Matter Is

:Mass: the amount of matter in an object.


Volume: the amount of space an object takes up.



Weight: (on Earth) a measure of the force of gravity between Earth and an object.  


Density: a measure of how tightly packed matter is; the a mount of mass contained in a given volume.


Buoyancy: the upward push on an object by the liquid (or gas) the object is placed in.


Conduct: allow heat or electricity to flow through readily.



Insulate: not allow heat or electricity to flow through readily.



Element: a basic building block of matter; a pure substance that cannot be broken down into anything simpler.


Compound: a chemical combination of two or more elements into a single substance.



Atom: the smalest unit of an element that still has the properties of the element.


Proton: a particle with a positive charge in the nucleus of an atom.


Neutron: an uncharged particle in the nucleus of an atom.


Electron: a particle with with a negative charge moving around the nucleus of an atom.


Nucleus: the dense center part of an atom.


Molecule: a group of more than one atom joined together that acts like a single particle.


Invisible Light

Electromagnetism: the production of magnetism by electricity and the production of electricity by magnets.


Electromagnetic spectrum: all the wavelengths of visible and invisible light in order from short (gamma rays) to long (radio).


Laser: a device that produces a thin stream of light of just a few close wavelengths.

  




domingo, 15 de agosto de 2010

Album : Invisible Light



Introduction




In this album we are going to learn how does the imbisible light work and were there are. And if theuy can harm ourself or help us.




Blu Ray



                 Blu-ray disc (official abbreviation BD) is an optical disc storage medium designed to supersede the standard DVD format. Its main uses are for storing high definition video, Playstation 3 video games, and other data, with up to 25 GB per single-layered, and 50 GB per dual-layered disc. Although these numbers represent the standard storage for Blu-ray Disc drives, the specification is open-ended, with the upper theoretical storage limit left unclear. The discs have the same physical dimensions as standard DVDs and CDs





Radio Waves: 




Radio Waves are the longest waves of the electromagnetic spectrum.  You do not see them and do not hear them. Broadcast stations use them to carry signals in a kind of code AM or FM.
In AM the height of the waves is changed to carry signal. In FM the frecuency changes.

Microwaves :


       
A microwave oven uses electromagnetic waves, too. Microwaves are shortwaves radio waves. Water in foods absorb microwaves very readily. The
energy from the absorbed microwaves speeds up the water molecules inside the food.


Infrared light: 



Infrared means "just beyond red."  Infrared wves are next to visible red waves in the spectrum.  When you stand in sunlight, it is the Sun´s infrared waves that warm you.  All objects give off infrared waves, depending on their tempersture.  Warmer objects give off more infrared waves than cooler objects do.

Ultraviolet Light:


    
Untraviolet (UV) light is made up of waves just shorter than visible violet light on the spectrum.  UV light causes chemical changes.  It can produce vitamin D in your body.  You need vitamin  for healthy bones and teeth.  Ultraviolet light produces vitamin D in milk.  Hospitals use ultraviolet light to kill harmful bacteria in equipment used in operating rooms.  However, UV light can cause harm.  UV light from the Sum causes a sunburn.  Scientist have found that UV light can also cause some forms of cancer on the skin.


X rays and Gamma rays



The shortest wavelengths of the spectrum - X rays and gamma rays - have great penetrating power.  X rays can pass right through most objects.  Thicker or denser objects tend to absorb X rays.  This means that X rays can produce a picture when they pass through an arm or leg, or your jaw.  The denser objects, such as bones and teeth, can show up very clearly on the finished picture.

Extra Information:

The distinction between X-rays and gamma rays has changed in recent decades.  Originally, the electromagnetic radiation emitted by X-rays tubes had a longer wavelenght than the radiation emitted by radioactive nuclei (gamma rays).  Older literature distinguished between X-and gamma radiation on the basis of wavelength, with radiation shorter than some arbitrary wavelength, such as 10-11 m, defined as gamma rays.  However, as shorter wavelenght continuos spectrum X-rays sources such as linear accelerators and longer wavelenght gamma ray emitters were discovered, the wavelenght bands largely overlapped.  The two types of radiation are now usually distinguished by their origin: X-rays are emited by electrons outside the nucleus, while gamma rays are emitted by the nucleus.

German physicist Wilhelm Rontgen is usually credited as the discoverer of X-rays because he was the first to systematically study them, throught he is not the first to have observed their effects.  He is also the one who gave them the name X-rays, though many refered to these as Rontgen rays for several decades after their discovery.

Among the important early researchers in X-rays were Ivan Pulyiu, William Crooker, Johann Wilhelm Hittorf, Eugen Goldstein, Heinrich Hertz, Philipp Lenard, Hermann von Helmholtz, Nikola Tesla, Thomas Edison, Charles Glover Barkla, Maz von Laue and Wilhelm Conrad Rontgen. 



Conclusion

In this album we have learned that the rays ar every were in our planet and in the universe. We use them in our daily lives in our houses and every were we are. And also they can harm our skin. And also they help us.



jueves, 12 de agosto de 2010

Bioluminecence: Light produced by living organism.


light ray: a straight-line beam of light as it travels outwards of it source.


Law of Reflection: the angle of an incomming light ray equals the angel of the reflected ray.


Concave mirror: a mirror that curves in on the shiny side.


Convex mirror: a mirror that curves out on the shiny side.


Opaque: completely blocking light from passing through.


Transparent: letting all light through, so that objects on the other side can be seen clearly.



Translucent: letting only some light through, so that objects on the other side appear blurry.



Polarization: allowing light vibrations to pass through in only one direction.

Refraction: the bending of light rays as they pass from one substance into another.

Convex lens: a lens that curves outward (is thicker at the middle than at the edges) and brings light rays together.


Concave lens: a lens that curves inward (is thicker at the edges than at the middle) and spreads light rays apart.

Prism: a cut piece of clear glass (or plastic) with two opposite sides in the shape os a triangle or other geometric shape.

Spectrum: a band of colors produced when light goes through a prism.


Primary color: red, green, or blue; mixing these colors can produce all the colors of the spectrum.

Primary pigment: magenta, cyan, yellow; material with any of these colors absorbs one primary color of light and reflects the other two.