VOCABULARY:

VOCABULARY:

UNIT 5:

Have a lie-in: Get up late
Eventually: At some later time
Have a sleep over: Sleep in a friend´s house

UNIT 7:

Fightback: Return to fight
Polite: Showing good manners;  polite , courteous.
Bite: To cut or tear with the teeth.
Shy: Timid

MICHAEL SCHUMACHER

Here is the link to the prezi.

http://prezi.com/em_l3g1j6_lm/?utm_campaign=share&utm_medium=copy&rc=ex0share

HELIUM

PROPERTIES:

Helium is a chemical element of atomic number 2, the symbol He and Atomic standard of 4,0026 weight. It belongs to group 18 of the periodic table of the elements. His boiling point is -268,93º C and his melting point is -272,20º C. Helium have 2 protons, 2 neutrons and 2 electrons. Inhaling a small amount of helium generates a change in the quality and timbre of the human voice. Helium is the second lightest element and the second most abundant in the univers. Most of the helium in the universe is present in the form of the isotope (4/2He). Traces of helium due to the radioactive decay of some elements are in the Earth's atmosphere. On Earth, the lightness of helium has caused its evaporation of the cloud of gas and dust from which the planet, was formed.

DISCOVERY:

 Pierre Jules César Janssen was a French astronomer, discoverer of the chemical element helium, this person  devised a system to observe solar prominences without having to operate the eclipses. On 18 August of that same year, as he watched an eclipse of the Sun in the India, he observed a bright yellow line. On 20 October of the same year, the English Astronomer Lockyer also observed the same yellow line in the solar spectrum and concluded that it was caused by an unknown element. Subsequently showed that this was a new element to date: helium.

APLICATION:

Helium is used to :

1. It is used to cool the superconducting magnets
2. It is used to fill airships and hot air balloons.
3. Can be used to detect leaks.
4. Used in lasers to read bar codes.