Monday, January 31, 2011
INTRODUCTION
PHYSICS Physics is the systematic study of the way objects, matter and energy moves,changes and interacts.It is really concerned with how fasts things move, When they move and what causes things to move, those things can be the very large like stars or galaxies or the very small groups of objects or single objects it is also about what make up the fundamental building blocksof the reality we live in.
WHY IS PHYSICS IMPORTANT?
Studying the way things moves and interact the world is fundamentally usefull in all sorts of way. In some cases it is crucial to our survival. Interestingly our own brain have needed to develop an automatic understanding of physics for example being able to walk or balance requires our brain to make lots of calculation about friction and forces physics is crucial to virtually all of our modern technology, conveniences and infrastructure.From computers to cameras and everyday appliances
INTRODUCTION ABOUT THIS PROJECT
When we look at things in the solar system, we try to measure what we see. This allows us to compare the many objects and to know how and where will they ,will move, what they consists....etc., In this first chapter may answers the simple questions about the solar system. Our solar system is belived to be about five billions years old and formed at same time as the sun. Our solar system consist of an average star we call the sun, the planets Mercury,Venus,Earth, Mars,Jupiter,Saturn,Uranus,Neptune, satellites to the planets,comets, asteroids andmeteroids. The sun is richest source of electromagnetic energy.The first chapter gives basic information about the all planets this will enchance once knowledge whom unknown face to the solar system.
The total energy of solar system is mainly contributed by the sun. Energy is most important part for living things,Without energy no one can be in earth. Now a days there is a demand in energy due to rises of consumption and population so we need a perfect alternative way of energy creation.Today world's energy requirement may fullfill by nuclear energy we know one kind of energy can convert into another kind, by this sentences nuclear energy can convert into electrical, heat etc. Nuclear energy gives basic information about What is nuclear energy? How we can produce nuclear energy? Generally nuclear energy is obtained during the process of nuclear fission and fusion.This chapter also gives some basic introduction to nuclear reactor and atomic bomb.There are some causes in obtainig energy from this process but we have not alternative way to escape from this one. Also one can understand how energy in the sun is formed by this chapter simply this chapter creates a way for unknown phaces to nuclear energy.
The nuclear energy provides 16% of world's electricity is the essential need of this decade people. Electricty chapter gives some details about what is background of elecricity.In BC (Before Christian year) Peoples woundered about attractive behaviour of materials .but they did not know how it happens"? This chapter gives pre history of magnetism and name factor of magnetism .Electricty and magnetism have a thick relationship between them. We can generate magnetic field arround a coil, while current electricity is passing through it.This is a simple electromagnet. This chapter can teach simple thing about electrmagnets and its applications to younger brains.
Electricity can obtain by electromagnetic force. Force can more objects (Newton's first law) and obtain energy when objects are moving under this one. It deals about force per unit area (Pressure) exerted by a fluid at rest, which branch of physics is hydrostatics. This chapter says how pressure vary with depth? and different type of pressures.This chapter explains the man of Euraeka's Principle and its application we can assure the image of object by observing reflected electromagnetic wave(Visible light) from that.We can converge or diverge the image by using lenses. The lense chapter gives fundamental fact and classification of lenses this one give details about how to rectify the eye defects by lenses? Every livining things eye made of lense it will pass the image sense to brain it is similarly to what camera is done why capturing an image. This chapter gives source basic differents between eye and camera consequently all these five chapters can give a basic view of physics.These chapters will enchance thoughts of ones who enter to the next stage of physics
Tuesday, January 25, 2011
Atom Bomb
The working principle of atom bomb is nuclear fission. Here an uncontrolled fission reaction takes place. When the bomb explodes large quantity of energy in the form of heat, light and radiation is released, a temperature of millions of degrees and pressure of millions of atmosphere are produced. Human life is impossible under such explosion. These bombs were used in World War II and were exploded over Hiroshima and Nagasaki in Japan.
Principle
Principle
The splitting of atomic nuclei release enourmous energy. When a single free neutron strikes the nucleus of an atom of fissile material like U^235 and Pu^239, It usually knocks two or three more neutrons free energy is released when those neutrons split off from the nucleus,and newly released neutrons strilce other U^235(or Pu^239) Nuclei, splitting them in a same way,releasing more energy and more neutrons.This process is occur in the atomic bomb.
Nuclear Reactor
In nuclear fission, a very large amount of nuclear energy is liberated within an extremely small interval of time. Consequently, it is not possible to convert the nuclear energy for any useful purpose. So, a device becomes necessary to control the reaction in nuclear fission. Such a device is called nuclear reactor.
The nuclear energy from nuclear fission has many uses. A nuclear power plant produces electric power from the nuclear energy of nuclear of nuclear fission.
A Nuclear reactor is a device in which nuclear chain reactions are initiated, controlled and sustained at a steady rate.
A Nuclear reactor is used to convert nuclear energy into heat and electrical energy.
The Production Of Nuclear Energy
A nucleus makes up most of the mass of every atom. This nucleus is held together by an extremely powerful force called nuclear force. Because of this force, a large amount of energy is concentrated in the nucleus.
Any process in which a particle penetrates a nucleus and changes it to produce nuclear energy is called nuclear reaction. In nuclear reaction, nuclear energy is produced by two processes namely nuclear fission and fusion.
The process of breaking up of the nucleus of a heavy atom into two or more smaller nuclei with the release of a large amount of energy is known as nuclear fission.
( or )
Nuclear fission is a nuclear reaction in which nucleus of a heavy atom splits into smaller atoms(parts)with lot amount of energy.
The energy produced is known as nuclear energy, because of the original mass of the sum of the masses of the products produced after nuclear fission. The difference between these masses before and after the nuclear fission is converted into nuclear energy.
Nuclear fusion is a process in which two or more light nuclei combine to form a heavy nucleus. The difference in mass is converted into energy. The energy liberated is called thermo-nuclear energy. For example, the energy production in the sun and stars is due to the nuclear fusion. In sun, four hydrogen nuclei combine to form a helium nucleus at very high pressure and temperature. Also, hydrogen bomb works by the principle of nucleus fusion. It is more powerful than an atom bomb.
Nuclear fusion produces s more energy than nuclear fission, but nuclear fusion requires certain energy surrounding to happen.
Nuclear Fission
The process of breaking up of the nucleus of a heavy atom into two or more smaller nuclei with the release of a large amount of energy is known as nuclear fission.
( or )
Nuclear fission is a nuclear reaction in which nucleus of a heavy atom splits into smaller atoms(parts)with lot amount of energy.
The energy produced is known as nuclear energy, because of the original mass of the sum of the masses of the products produced after nuclear fission. The difference between these masses before and after the nuclear fission is converted into nuclear energy.
Nuclear Fusion
Nuclear fusion produces s more energy than nuclear fission, but nuclear fusion requires certain energy surrounding to happen.
NUCLEAR ENERGY
Nuclear energy results from the changes occurring in the nucleus of atoms. Scientists and Engineers have found many uses for the nuclear energy, especially in producing electricity.
Nuclear energy provides 16% of world's electricity.Nuclear energy is produced naturally(sun and star's energy)and may made operations under human controll(Nuclear reactors).
Nuclear energy provides 16% of world's electricity.Nuclear energy is produced naturally(sun and star's energy)and may made operations under human controll(Nuclear reactors).
Electric Bell
Construction
The electric bell consists of an electromagnet. In front of the electromagnetic poles, there is a soft iron piece. The soft iron piece is attached to the vibrator. Vibrator is a rigid metallic strip having a hammer at its free end. The gong is fixed against the hammer. Also, platinum strip is fixed to the vibrator. By adjusting screw in contact-maker, contact is made with a platinum strip at a point. This point is called contact point.
Working
When key is pressed, the electric circuit is completed and the current flows through the electromagnet The electromagnet becomes magnetized and attracts the soft iron piece. When the soft iron piece is attracted, the hammer strikes the gong. The gong produces the sound. This movements breaks the circuit at the contact point between the screw and platinum strip, so that the current stops flowing. The electromagnet gets demagnetized and thereby the soft iron piece is released. The soft iron piece falls back to the original position and makes contact with the screw. The electric circuit is completed again. The above process keeps on repeating. Therefore the soft iron piece keeps on vibrating and giving rise to the continuous ringing of the bell. Electric bells are used as door bells and buzzers.
Uses of Electromagnets
- Electromagnet is an essential part of electric generators, motors, telegraph instruments, loudspeakers, earphones and telephone receivers.
- Electromagnets are also used in electric bells and tape recorders,VCR's Hard disk and Magnetic locks.
- Electromagnets attached to cranes are used to lift huge loads.
- Electromagnets are used for making new magnets or remagnetising the old ones.
- Electromagnets are used to seperate the magnteic materials from non- magnetic materials.
Electromagnets
An electro magnet is a type of magnet in which the magnetic field is redused by the flow of the electric current.
1. Number of turns in the coil
2. The strength of the current
3. The nature of core material.
The piece of soft iron nail is placed inside a circular coil. Here, soft iron nail is called core. When current is passed through the coil, the soft iron filings are brought near the soft iron nail, then the iron filling cling to the nail. On the other hand, the soft iron nail is demagnetised, when the current is stopped in the coil. This arrangement is called an electromagnet. The electromagnet is thus a temporary magnet. The strength of electromagnet will depend on,
1. Number of turns in the coil
2. The strength of the current
3. The nature of core material.
Electricity
The term "electricity" comes from the Greek word “electron,” which means, "amber". A Greek philosopher, Thales, noticed that a rubbed a piece of amber with a woolen cloth. As a result of friction, the amber acquired the property of attracting small particles of dust etc.. In other words, the amber becomes charged or electrified.
There are two kinds charges namely, Positive and negative.
MAGNETISM
A mineral discovered in the town of magnesia was found to have a strange property. It could attract pieces of iron towards it. This mineral is named Magnetite after the place where it was discovered. Later, it was found that magnetite is mainly composed of oxides of iron (Fe3O4 ). These are now known as Magnets. The study of magnetic properties is called Magnetism.
Comparison Between The Human Eye And The Camera
Similarities
| The Eye | The Camera |
| 1.A real and inverted image is Formed on the retina. 2.The iris controls the amount of light entering the eye. 3.The time of exposure of light is controlled by the eye lids | 1.A real and inverted image is formed on the photographic film. 2.The diaphragm controls the amount of light 3.The time of exposure of light is controlled by the shutter. |
Differences
| The Eye | The Camera |
1.The focal length of the eye lens can be changed by the action of ciliary's muscles 2.The retina retains the image only for a short time. 3. The convex lens of the eye is made of a transparent and flexible substance. | 1.The focal length of the lens cannot be changed 2.The film retains the image of the object Permanently. 3.The convex lens is made of a glass. |
The Defects Of The Eye
The two common defects of the eye are as follows.
1.Short Sight or Myopia
“The person having the short sight can see only the nearer object.” The eyeball of the person having short sightedness is longer than the normal sighted eye. When a parallel beam of light from the distant object is incident on the eye, the rays are brought to focus in front of the retina. Hence the image is not formed on the retina.
A concave lens of suitable focus length can rectify this defect. 2.Long Sight or Hypermetropia
1.Short Sight or Myopia
A concave lens of suitable focus length can rectify this defect. 2.Long Sight or Hypermetropia
“The person having the long sight can see only the distant object.” The eyeball of the person having long sightedness is shorter than the normal sighted eye. When the light from the nearer subject is incident on the eye, the rays are focused behind the retina. Hence, the image is not formed on the retina.
A convex lens of suitable focal length can rectify this defect.
Perception Of Sight
Light from the object is refracted by the cornea through the aqueous humour, iris and pupil onto the eye lens. The eye lens focuses the image through the vitreous humour onto the retina. These images are received by the light sensitive cells of the retina and they transmit the impulses to the brain through the optic nerves.
The ciliary muscles change the shape of the lens and adjust the focal length according to the distance of the objects. Normally the focal length of the eye lens will be about 2.5cm.
Camera
The Camera consists of a convex lens supported at one end of a light proof box and a light sensitive film at the other end. The distance between the lens and the film can be adjusted. There is a shutter behind the lens.
When we click our Camera, the shutter opens and the light from the object passes through the lens. The lens forms a real, diminished and inverted image on the film. A diaphragm of Variable aperture is also provided so that the amount of light entering the Camera can be controlled.
Monday, January 24, 2011
LENSES
A lens is a portion of a transparent medium bounded by two surfaces both of which are usually spherical or one Surface spherical and the other plane. There are two types of lenses. They are
1.CONVEX LENS
A Convex lens is thick at the middle and thin at the outer region. A parallel beam of Light rays. After refraction through a convex lens converges. Therefore, this lens is called as converging lens.
2.CONCAVE LENS
A concave lens is thin at the middle and thick at the outer region. A parallel beam of light rays after reflection through a concave lens diverges. Therefore, this lens is called as diverging lens.
Submarines
According to Archimedes’ principle, when a body is immersed in a liquid, it suffers an apparent loss of weight equal to the weight of the liquid displaced by it.
The boat may be sunk lower in the water by admitting water into the internal tanks. Now the free surface of water AB may be much above the boat (b). Pumps are used for emptying the water tanks, thus brining the boat again to its original surface level.
Applications of Archimedes Principle
Archimedes’ principle is used to find the specific gravity of liquids and solids. This principle is also used in the submarines.
Archimedes's principle
A bucket fully immersed under water in a well appears to be very light. When this bucket is brought above the water level it weighs quite heavy. When the bucket is under the water level, the liquid displaced by the bucket exerts an upward force on it. This is known as the resultant up thrust (or) buoyancy.
Archimedes’ principle states that, “when a body is immersed in a liquid it suffers an apparent loss of weight equal to the weight of the liquid displaced by it”.
Archimedes’ principle states that, “when a body is immersed in a liquid it suffers an apparent loss of weight equal to the weight of the liquid displaced by it”.
Effect Of Atmospheric Pressure
Take a tin can. Remove the lid and pour some water into it. Heat the can for a few minutes. The water vapor displaces most of the air in the can. Close the can with the lid tightly and stop heating. Cool the can under the tap water and observe what happens to the can. When cold water is poured on the can, the steam condenses into water and the pressure inside the can decrease. The atmospheric pressure outside the can is higher than the pressure inside the can and soothe tin can gets crushed. This experiment shows the existence of the atmospheric pressure.
Atmospheris Pressure
- The envelope of air surrounding the earth is called atmosphere.
- It extends up to a height of about 800km.
- The density of air decreases as height increases.
- Air surrounds the earth because of the gravitational pull of the earth on it.
- The atmospheric pressure is caused by the weight of the air.
- “Once atmospheric pressure is the weight of the air exerted over an area of one square meter”.
Variation of Pressure with Depth
Take a tall metal cylinder with a few holes on its side at various levels. Each hole has the same diameter. The holes are initially closed by corks. The cylinder is filled with water. When all the holes are opened, water rushes out through them but with varying forces. The water from the lowest hole falls for away from the cylinder.
This experiment clearly shows that the pressure of the liquid increase with depth.
Pressure
Pressure is defined as the force acting over unit area. The unit of pressure is Newton/m^2
(or)
Pressure is defined as the thrust acting normally on unit area, unit N/m^2 or Pascal.
(or)
Pressure is defined as the thrust acting normally on unit area, unit N/m^2 or Pascal.
HYDROSTATICS
Hydrostatics is the branch of science of fluids at rest and it is a sub field with in fluid mechanics.
Hydrostatics deals with the equilibrium of fluids. Liquids and gases can flow freely and for this reason, they are called fluids. Fluids do not have a fixed shape like solids.
Neptune
- It is very far off and can be seen only through telescopes.
- Discovered on September 23, 1846.
- Neptune has a faint and fragmented ring system.
- The temperature of the neptune is 55K(-218.c)
Uranus
- It is a third largest planet and appears green when seen through a telescope.
- Sir William Herschel announced its discovery on march 13, 1781.
- It is the coldest planetary atmosphere in the solar system with minimum temperature of 49K(-224.c).
- It has a complicated planetary ring system in the solar system after saturn's.
Saturn
- Galileo first observed it with a telescope in 1610.
- It is seen with naked eyes as a bright yellow planet.
- Saturn has several beautiful rings around it.Consisting mostly of ice particles with a smaller rockey debris and dust.
- The division between the main and the outer rings is called "Cassini's division".
Jupiter
- Jupiter is the largest planet of our solar system.
- It is covered by clouds composed of ammoniya crystals and an enormous red spot can be seen in the clouds.
- It's upper atmosphere is composed of 88-92 % of Hydrogen and 8-12 % of Helium.
Mars
- Even for naked eyes Mars appears reddish.
- The Mars is visible from the earth for most part of the year.It is mostly reffered to as the "Red planet" because of its reddish appearence.
- Mars has relatively thin atmospher.The atmosphere on marss consists 95% of carbon-di-oxide.
Earth
- The earth is the only planet known to have life (geological activity) in the universe.
- Earth is the third planet from the sun and the fifth largest of the eight planets in the solarsystem.
- The earth rotates once in 24 hours about an imaginary axis that passes through its north and south poles. The day and night on the earth occur due to this rotation.Earth radius is 6371Km.
- The earth completes its journey around the sun in 365.25 days.With 29.78Km/s speed.
- The axis of rotation of the earth with respect to its orbits plane is tilted by an angle of 23.5.This tilt causes changes in seasons on the earth.It has one natural satellite is called moon.
Venus
- Venus is similar to the earth in respect of radius,mass(0.815 Earth masses) and density. So,it has been rightly called the earth's twin.
- Venus is a brilliantly shining planet as it reflects as much as 85% of the sunlight falling upon it.
- Venus reaches its maximum brightness shortly before sun rise or shortly after sun set. For which reason it is often called the morning star or the evening star.
- Venus appears as an evening star just above the western horizon and it also appears in the eastern sky as morning star.
- Surface temperature of the venus is 700k,although all planetary orbits are elliptical, venus is closest to circular.
Mercury
- The planet nearest to the sun is called Mercury.Mercury Is the smallest planet in the solar system. The surface of Mercury is full of craters of different sizes similar to that of the moon.
- Mercury has almost negligible atmosphere consists of atoms blasted off itds surface by the solar wind
- The surface temperatures range from about 90K to 700K(-183C to 427C).
- Mercury is hidden in the sun's glare most of the time
- So it is occasionally visible just before the sunrise or just after the sunset
Planets
- The solar system consists of Eight planets.They are Mercury,Venus,Earth, Mars(four inere planets).Jupiter,Saturn,Uranus,Neptune ( four outer planets).
- The motion of planets in their orbits is due to the force of gravitation of the sun on them. The planet Mercury is nearest to the sun and Neptune is farthest from the sun.
- Jupiter is the largest of all the planets and Saturn is the second largest.
- Between Mars and Jupiter there is a belt of minor planets are called asteroids. They revolve in elliptical orbits around the sun.
- Mercury and Venus are called inferior planets,as their orbits are smaller than that of the earth.The other planets are called superior planets whose orbits are larger than that of the earth.
- In the solar system,only the sun emits its own light. The planets appear bright by reflecting the light falling on them from the sun.
- In addition on the sun,Eight planets and their satellites,and asteriods,the solar system contains many bodies called comets and metetors.
- It is believed that the sun has a total life of about 10 billion years. Out of which,nearly 5 billion years is already over.
- The sun is made up of extremely hot gases giving out huge flames.Also, sun is the only source of heat and light energy to all the heavenly bodies that revolve around it.
SOLAR SYSTEM
INTRODUCTION
PHYSICS Physics is the systematic study of the way objects, matter and energy moves,changes and interacts.It is really concerned with how fasts things move, When they move and what causes things to move, those things can be the very large like stars or galaxies or the very small groups of objects or single objects it is also about what make up the fundamental building blocksof the reality we live in.
WHY IS PHYSICS IMPORTANT?
Studying the way things moves and interact the world is fundamentally usefull in all sorts of way. In some cases it is crucial to our survival. Interestingly our own brain have needed to develop an automatic understanding of physics for example being able to walk or balance requires our brain to make lots of calculation about friction and forces physics is crucial to virtually all of our modern technology, conveniences and infrastructure.From computers to cameras and everyday appliances
INTRODUCTION ABOUT THIS PROJECT
When we look at things in the solar system, we try to measure what we see. This allows us to compare the many objects and to know how and where will they ,will move, what they consists....etc., In this first chapter may answers the simple questions about the solar system. Our solar system is belived to be about five billions years old and formed at same time as the sun. Our solar system consist of an average star we call the sun, the planets Mercury,Venus,Earth, Mars,Jupiter,Saturn,Uranus,Neptune, satellites to the planets,comets, asteroids andmeteroids. The sun is richest source of electromagnetic energy.The first chapter gives basic information about the all planets this will enchance once knowledge whom unknown face to the solar system.
The total energy of solar system is mainly contributed by the sun. Energy is most important part for living things,Without energy no one can be in earth. Now a days there is a demand in energy due to rises of consumption and population so we need a perfect alternative way of energy creation.Today world's energy requirement may fullfill by nuclear energy we know one kind of energy can convert into another kind, by this sentences nuclear energy can convert into electrical, heat etc. Nuclear energy gives basic information about What is nuclear energy? How we can produce nuclear energy? Generally nuclear energy is obtained during the process of nuclear fission and fusion.This chapter also gives some basic introduction to nuclear reactor and atomic bomb.There are some causes in obtainig energy from this process but we have not alternative way to escape from this one. Also one can understand how energy in the sun is formed by this chapter simply this chapter creates a way for unknown phaces to nuclear energy.
The nuclear energy provides 16% of world's electricity is the essential need of this decade people. Electricty chapter gives some details about what is background of elecricity.In BC (Before Christian year) Peoples woundered about attractive behaviour of materials .but they did not know how it happens"? This chapter gives pre history of magnetism and name factor of magnetism .Electricty and magnetism have a thick relationship between them. We can generate magnetic field arround a coil, while current electricity is passing through it.This is a simple electromagnet. This chapter can teach simple thing about electrmagnets and its applications to younger brains.
Electricity can obtain by electromagnetic force. Force can more objects (Newton's first law) and obtain energy when objects are moving under this one. It deals about force per unit area (Pressure) exerted by a fluid at rest, which branch of physics is hydrostatics. This chapter says how pressure vary with depth? and different type of pressures.This chapter explains the man of Euraeka's Principle and its application we can assure the image of object by observing reflected electromagnetic wave(Visible light) from that.We can converge or diverge the image by using lenses. The lense chapter gives fundamental fact and classification of lenses this one give details about how to rectify the eye defects by lenses? Every livining things eye made of lense it will pass the image sense to brain it is similarly to what camera is done why capturing an image. This chapter gives source basic differents between eye and camera consequently all these five chapters can give a basic view of physics.These chapters will enchance thoughts of ones who enter to the next stage of physics
ABOUT ME
A.PARRIMALAM,
M.Phil Scholar,
Department of Education,
Mother Teresa Women’s University,
Kodaikanal – 624 101 Tamil Nadu, India.
I have created a blog on Developing Blogs to Physics for class 8th of the Tamilnadu stateboard .Blog (a contraction of the term "web log") is a web site, usually maintained by an individual with regular entries of commentary, descriptions of events, or other material such as graphics or video. Entries are commonly displayed in reverse-chronological order. "Blog" can also be used as a verb, meaning to maintain or add content to a blog. Many blogs provide commentary or news on a particular subject; others function as more personal online diaries. A typical blog combines text, images, and links to other blogs, Web pages, and other media related to its topic.
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