# Science

Culture &amp; Science - Science
Tuesday, 19 March 2013 14:08

## Article Index:

1. What is the law of Coulomb
2. Formulas Coulomb's Law

### What is Coulomb's law:

• We can define the Coulomb law as the law that determines the properties of electrostatic force arising from one or more electrical forces. It closely resembles the Law of Universal Gravitation.
•   It was stated by Charles-Augustin de Coulomb in 1785, thanks to a torsion balance with which the experiments performed (thus measuring the force of attraction or repulsion suffering two electric charges).
• As stated by Coulomb can say that: "The electric force exerted between two electrically charged bodies is directly proportional to the product of their charges and inversely proportional to the square of the distance that separated".

### Formulas Coulomb's Law:

The equation of Coulomb's law is:

• F = force vector is suffering electrical loads. It can be attractive or repulsive, depending on the sign appears (depending on whether the positive or negative charges).
• q = loads are subjected to the experiment.
• Epsilon = permittivity.
• ud = direction vector connecting the charges q1 and q2.
• d = distance between charges.

The ratio 1/4 (pi) E is called Coulomb constant.

This law is also used for various loads (nth), the following equation:

indicating the force caused by loads regarding a i, q.

• As we can see by simple comparison, is very similar to the equation of universal gravitation, formulated by Isaac Newton

Application of Coulomb's law:

• In case you have been very clear, or you need to give you an example of the application of Coulomb's law, perhaps one of the simplest is that of polythene bags.
• Have you ever noticed that if you break a polythene plastic, which usually carry these appliances to protect them, possibly some piece will be attached to your clothes?.
• Also costs quite suddenly remove it or not re-stick. This happens because we are "charged" by the friction of our clothes, air, etc.. these charges are opposite to the plastic and it is attracted to us and beats us.
• Another example is to rub a rule against our clothes, then went through a sheet of paper and see how it stands up. Or put two balloons inflated, the rub and you can see the action of the Coulomb force.

Video on Coulomb's law:

### Other items of interest in Espaciociencia:

Culture &amp; Science - Science
Tuesday, 19 March 2013 14:08

I recently came the news that he could resurrect the mammoth thanks to advances in genetics , and also said he might even do it with Neanderthals . And is that both species have managed to sequence the genome altogether. Now they have gone further, and in an article in New Scientist named to the 10 extinct animals that could revive in a few years.

All that is needed is a well-preserved specimen which to extract a DNA sample, and thus obtain genetic information that could help complete the genome of these extinct animals.

So you just could do with some animals become extinct relatively recently, such as the dinosaurs is very difficult to be able to get enough genetic material to complete a genome. The DNA in the bones can not survive more than a million years.

So scientists are now sequencing the genomes of several extinct animals to someday bring them back to life. This should get some kind alive today that is similar, so that you can grow the embryo.

New Scientist has made the selection of the 10 animals that would be brought to life again. This has been based not only on the ability that can be made, but also with those animals charisma extinct.

Obviously to bring back to life animals that are extinct for a reason that has nothing to do with man, it would be a problem, because we should think about where they would live, etc.. But do not spoil the fun, and get on with the game, let's see the list:

##### 1 - Homo neanderthalensis. Extinct about 30,000 years ago

In the first place we have the Neanderthal undoubtedly one of the most charismatic extinct creatures, and the last human species among us modern humans. I have been working on finding the Neandertal Genome years, and has successfully completed a draft thereof. were believed to the end of 2009 will have the full genome.

##### 2 - T igre Sabretooth ( Smilodon fatalis ) Extinct 11,000 years ago

There are many specimens of saber tooth tiger gives complete, and lions are similar enough to make surrogate.

##### 3 - giant short-faced bear ( Arctodus simus ). Extinct 10,000 years ago

These huge bears on all fours had the height of a man is the giant version of the current bear. Frozen discovered many specimens as in the case of the mammoth .

##### 4 - Tasmanian Tiger or Thylacine ( Thylacinus cynocephalus ). Extinct in 1936.

The last of its kind died in Hobart Zoo in 1936, so they have enough uncontaminated tissues to get a good quality DNA.

##### 5 - Gliptodonte ( Glyptodon clavipes ). Extinct for 10,000 years.

This armadillo supergiant would be very interesting to see him alive, if their bones are already huge. (The list continues after the image)

##### 6 - The Dodo ( Raphus cucullatus ). Extinct in 1690

This bird so famous and so interesting of the islands Mauritius has a well-preserved specimen, and in 2002 geneticists at Oxford University and is working with its genome.

##### 7 - woolly rhinoceros ( Coelodonta antiquitatis ). Extinct about 10,000 years ago.

Like the mammoth, the giant hairy rhinoceros that was less than two meters high has been preserved in many specimens frozen.

##### 8 - Megatherium Giant Sloth ( Megatherium ). Extinct 8000 years ago

When stood on his two feet could reach up to 6 meters high. There are many remains of which can get DNA, and it has been so long since extinct.

##### 9 - giant deer or Irish elk ( Megaloceros giganteus ). Extinct 7700 years ago.

This giant deer could reach two meters in height, with antlers that could measure up to 4 meters wide. There are sufficient to collect DNA specimens and is very similar to the current deer, only giant.

##### 10 - The Moa ( Dinornithidae ). Extinct by 1500.

This bird similar to an ostrich could reach up to three meters high, and living in New Zealand, there are enough bones and even eggs, from which genetic material obtained.