Exercise 1
We find it interesting that scientists teach their students.
Scientists saben como enseñar a sus alumnos a realizar los experimentos y en caso de que algo les salga mal que puedan volver a intentarlo de nuevo, porque bajo nuestro punto de vista es así como se aprende equivocándose. Nosotras creemos que si a estos alumnos les enseñara otro tipo de profesores no aprenderían lo mismo, ya que una persona puede enseñar mejor y dar mejores ejemplos si ya lo ha vivido antes, para así enseñarles a como salir adelante.
Tenemos muchos ejemplos de científicos que han sacado adelante a otros muchos científicos como es el ejemplo de J.J Thompson que fue profesor de Rutherford y este a su vez de Bohr, y podríamos continuar la list, so that this shows that thanks to the teachers who have had, they also have been some teachers and some very good scientists.
Exercise 2
The main difference between physics and chemistry is the following:
Physics is the science that studies the properties of matter and energy, considering only attributes able to measure, while chemistry is the science that studies the structure, properties and transformations of matter from its atomic composition, physics has changed a lot over the years, to the point that he felt he could be part of biology as this photo shows.
In this picture you can see and describe the physics for biologists.
The phrase to which Rutherford refers to as "all science, or is physical, or a collector of stamps" what this phrase means from our point view is that a stamp collector all he does with them is to see and know more about them but not useless, and compares it with the physics in their view not useless.
The other phrase that Rutherford says is "I have changed many times in my life, but never so sharp as in the metamorphosis of physical chemistry, what this phrase means is that you do not understand how he managed to win a prize nobel something that felt a metamorphosis that I thought was not going to be good for nothing.
Exercise 3
Nikola Tesla was a physicist, mathematician, electrical engineer and a famous inventor. Electrical theory revolutionized
developing the basis for generating alternating current.
had a big fight with Edison since it maintained its position that the current Nikola while defending his position on the advantages of alternating current, which was eventually won. While
had another confrontation with Marconi as he won the Nobel Prize since it presented the radio that he had actually created Nikola.
Exercise 4
What Unlike the fluorescence of phosphorescence?
From had plenty of time, geologists, physicists and chemists knew fascinating natural phenomena called "luminescence." There were two kinds of minerals (including organics) luminescent: fluorescent , emitting a strange blue light when stimulated by external radiation, and the phosphorescent , whose emission remained green even when they are kept light. The phosphorescence had to be stimulated by normal light.
What are X-rays?
Just over a century radiation was found (then unknown and hence the name of X-ray ) having the property of penetrating the opaque. X-rays are electromagnetic radiation, such as visible light or ultraviolet and infrared radiation, and the only thing that distinguishes them from other electromagnetic radiation is the so-called wavelength, which is order of 10 -10 m (equivalent to the unit of length is known as Angstrom) X rays are invisible to our eyes, but produce visible images when using photographic plates or special detectors for it.
X-rays became even more popular than the picture for obvious reasons: the field of medicine, which are used to perform X-rays, angiograms (study of blood vessels) or so-called CT scans. And the use of X-rays has been extended to the detection of flaws in metals and analysis of paintings.
How X-rays were discovered?
be discovered X-rays n by chance.
In 1895, while the physicist William Conrad Roentgen was experimenting with cathode rays realized that "a screen more than a meter from the unit are illuminated in a rather unexpected."
Realizing that the distance was great to work outside of the cathode rays, should be understood that other types of rays that were taking place. In his observation he realized that the rays are not deviated even crossed the solids. In this way, and for this reason, were discovered These rays were called X.
The first radiograph was made to his wife's hand.
What is radioactivity?, How was it discovered?
According account book, what happened to Becquerel. He was eager to expose the radiant sun a plate, since he had to give another lecture at the Academy and, after so many cloudy days, he despaired and thought that would reveal the board anyway to talk about the effects of weak phosphorescence. It turned out that the image of the currency that had come between plaque and uranium salts out as sharp as if they had been excited by light. The talk raised more boredom than anything else, but Becquerel was very impressed.
repeated that a thousand times, and leaving all the lights on in the bottom of a drawer, and concluded that the salt emitted rays that had nothing to do with phosphorescence. Among other things because the salts of uranium, not too impressed phosphorescent plates. Then I did everything at these salts, the heated, chemically separated them, etc ... and concluded that the uranium was only emitting a new type of radiation.
After three generations working on a case desembloque an important finding and says it was a coincidence, is a bit unfair.
In a more systematic and heroic, and even science, marriage and Marie Curie Joliot showed that many substances, simple elements first and then emitted rays that could only come from their atoms. Radioactivity, the Curies and called this phenomenon was discovered, although it ignores the nature and provenance.
Later Becquerel published seven articles on the subject, and explained his reason through an image. On the left you can see that is made emissions of radioactive substances, and the right, X-ray Obviously, the quality of the latter was much higher. Conclusion: radioactivity is useless.
Why were important contributions Rutherford Curies and Becquerel's work?
how things were when Rutherford was interested in the new phenomenon. Ignoring the poor applications that are glimpsed, before a mystery is working to elucidate and that was that. This is the true spirit of science. This attitude is what has caused most major scientific revolutions. Until Curie in Paris and Cambridge Rutherford did not clarify what was the radioactivity, Becquerel did not realize the importance of their discovery.
For this reason, I think what really brought the Curies and Becquerel Rutherford was the great admiration he had for his work and made him realize what had doubtless discovered.
What are alpha, beta and gamma? sort them energy
Alpha radiation is less penetrating than beta. In mid-1902 he added a third type, even more pervasive than previous which was called gamma.
Today we know that alpha radiation is the emission of helium nuclei (two protons and two neutrons) from an unstable atomic nucleus, beta radiation are electrons emitted in disintegration process of beta and gamma rays are high-energy photons.
The alpha particles emitted by natural radionuclides are not able to pass through a sheet of paper or human skin and slow down a few centimeters of air.
However, if an alpha emitter is inhaled, swallowed or enters the body through the blood, can be very harmful. The
beta particles are electrons. The lower energy are stopped by the skin, but most of those present in natural radiation can penetrate. Like alpha emitters, if a beta emitter enters the body can cause serious damage.
The gamma rays
are the most pervasive types of radiation described. Gamma radiation frequently accompanies and sometimes beta to alpha. Gamma rays pass easily through skin and other organic substances, so it can cause serious damage to internal organs.
X-rays fall into this category are also photons, but with a lower penetration capacity than gamma.
What is the law of atomic decay? Why served as a method of geological dating?
The decay of a radioactive nucleus is a spontaneous process pro and it is impossible to predict when an atom is transmuted. If it is true that when a large number of radioactive atoms, we can show that the number of initial nuclei decreases after a while. 
The number of atoms that disintegrate in a given time is directly proportional to the number of atoms in the sample. The constant of proportionality is known as the decay constant.
This is an animation of how Cultural UP over time, the red balls are disintegrating (become black), there was also the time when the breakup takes place.
is called half-life (T), the time that must elapse before the amount of radioactive substance is reduced by half. The value of T can range from very small fractions of a second (short-lived isotopes) to millions of years (long-lived isotopes).
This law is related to geological dating, because if the shows you want dating has elements such as lead, can you tell what year is about because we know what rate of decay has this element.
Currently, he continues to use this discovery, the only thing is that we now know the name of carbon-14.
Carbon 14
The carbon 14 is an isotope of carbon formed in the upper reaches of the atmosphere from nitrogen. Therefore, the carbon-14 present in the atmosphere.
One of the systems used to the age of fossils is the carbon-14 method, but has a number of problems, the most basic is that it is valid to date fossils of more than 50,000 years. By measuring the amount of carbon 14 and nitrogen that exist in the fossil's age can be known about it.
But there are big problems when trying to date the age of a fossil:
The first problem: the concentration of carbon in the atmosphere today may not be the same as it was when it died. To calculate the amount that had previously should consider several things.
The second problem: When calculating the carbon age from talking about radiocarbon years, and must distinguish radiocarbon years to calendar years. It is not the same to speak of 14,000 to 14,000 radiocarbon years calendar.
Other Issues: pollution, changes that fossil has suffered, and other variables.
Exercise 5
In 1911 took place in Manchester aiming to corroborate experience model Thomson atomic. Was carried out by Geiger, Marsden and Rutherford, and was bombarded with alpha particles (helium nuclei) a thin sheet of metal. The expected result was that the alpha particles passed through the thin with little deviation. To observe the location of particle impingement placed, back and sides of metal sheet, a phosphorescent screen.
Alpha particles have positive electric charge, and would be attracted to negatively charged and repelled by the positive charges. However, as in the Thomson atomic model of the positive and negative charges were distributed evenly, the field should be electrically neutral, and alpha particles would pass through the film without interruption.
However, the results were surprising. As expected, most of the particles passed through the film without interruption. But some had large deviations and, most importantly, a small number of particles bounced back. These events could not be explained by the atomic model of Thomson, Rutherford left so that the model and developed other, suggesting what is known as nuclear atom. In 1913 the Rutherford model was replaced by that of Bohr.
This experiment was conducted with Mica, with gold and platinum leaf.
Mica Thompson was as sponges positive electrical charge with electrons embedded in it understandable. From the electrical standpoint, the atoms did not have to deflect the alpha particle. But as the Mica is very thick, this makes the experiment and observed that as the alpha was so great Mica deteriorated.
When made with gold leaf, the experiment was much better, because being less thick than the Mica, the particles alpha were able to cross the gold leaf. But to do with platinum, found that the particles are more easily crossed.
With the phrase "It's like a rocket ship shot of good quality on a sheet of paper and bounce," Rutherford wanted to describe the way in which the alpha particle bounced hard against the gold foil, which first seemed to offer no resistance.
year or 6
As Rutherford's atomic model, electrons move in circular orbits and have a normal acceleration. But according to the principles of classical electromagnetism, an accelerating electric charge emits energy in motion, therefore, the electron orbits in a spiral would end up colliding with the nucleus, and this would be a continued loss of energy.
On the other hand, the electron would go through all possible orbits in a spiral around the nucleus, and therefore, the radiation should be continuous. However, the emission spectra of the elements are discontinuous.
nuclear interactions Types:
strong nuclear interaction
This force is responsible for holding together the nucleons (protons and neutrons) that coexist in the atomic nucleus, overcoming the electromagnetic repulsion between protons that have an electric charge of the same sign (positive) and making the neutrons, which have no electric charge, remain united among themselves and protons.
The effects of this interaction force are apparent only at very small distances (less than 1fm), size of atomic nuclei and are not perceived at distances greater than 1 fm. This feature is known as short-range be , as opposed to the gravitational force and electromagnetic force are far reaching (actually the scope of these two is infinite).
weak nuclear interaction
In the standard model of particle physics, this is due to the exchange of W and Z bosons, which are very massive. The most familiar effect is beta decay (of neutrons in atomic nuclei) and radioactivity. The word "weak" derives from the fact that a field forces is 10 13 times lower than the strong nuclear force, yet this interaction is stronger than gravity over short distances.
electromagnetic interaction
is the interaction that occurs between electrically charged particles. From a macroscopic point of view and set an observer, usually separated into two types of interaction, electrostatic interaction, which acts on charged bodies at rest relative to the observer, and the magnetic interaction, which acts only on charges in motion relative to the observer.
particles fundamental interact electromagnetically through the exchange of photons between charged particles. Quantum electrodynamics provides the quantum description of this interaction, which can be unified with the weak nuclear force as the electroweak model.
gravitational interaction
has to do with the force known as weight . Weight is the force with which any object is attracted by the mass of Earth. It takes this strength to measure the mass of objects quite accurately, using weight scales. Although the accuracy achieved is due to the the force of gravity between the Earth and the objects of its surface is similar in any place that is at the same distance from the center ground, but will decline if away from both the weight and the object to be weighed.
on other planets or satellites, the weight of objects depends on whether the mass of the planets or satellites is different (higher or lower) to the mass of Earth.
The effects of gravity are always attractive, and the resultant force is calculated for the center of gravity of both objects (in the case of Earth, the center of gravity is its center of mass, as in the Most of the heavenly bodies of characteristics).
Gravity has an infinite theoretical range, however, the force is greater if the objects are close to each other, and while this force will fade away. The loss of intensity of this force is proportional to the square of the distance that separates them. For example, if you move an object from another at twice the distance, then the force of gravity will be the fourth.
is one of the four fundamental forces observed in nature, being responsible for large-scale movements observed in the Universe: The Moon's orbit around the Earth, the orbit of planets around del Sol, etc..
Exercise 7
This is our shield and our scientific theme:
"The constant work dignified people."
