Earth Facts

 Earth Facts

Our planet earth is the largest of all the terrestrial planets and the only planet in our solar system which is not named after Greek or Roman gods. The word earth came from an Anglo-Saxon word Erda that means ground or soil. It was formed about 4.5 billion years ago. It is the third planet from the sun. Once it was believed to be the centre of the universe. It is the only planet which is known to support life.

Quick Facts: –

• This planet is an oblate spheroid that is made up of Iron, Oxygen and Silicon.
• Around 70% of our planet‘s surface is covered with water.
• Our planet has a strong magnetic field that is created by its molten iron core.
• It is the only planet with plate tectonics and liquid water on the surface. These tectonic plates are responsible for everything like earthquake, mountain formation etc.
• Our planet’s atmosphere contains 21% of oxygen.
• It is the only planet to support life.
• Talc is the softest known mineral of the earth that is used for many purposes.
• The planet has one large satellite, moon.
• Some changes occur in the gravitational force across the earth’s surface.
• The unexplored ocean of our planet contains more than 20 million tons of gold.
• Our atmosphere is made up of five layers.
• The earth takes 23 hours, 56 minutes and 4 seconds to rotate on its axis.
• It is the densest planet of the entire solar system.
• Our planet has seasons because it tilts slightly while orbiting around the sun.
• The distance between earth and the Sun is around 93 million miles.
• Mount Chimborazo is the furthest away from the center of our planet.
• The earth seen from moon also goes through phases.
• Antarctica is the coldest and driest continent on the planet.

Halley’s Comet

  Halley’s Comet

A comet can be defined as a small solar system body, orbiting Sun. They are made up of dust, ice and small rocky particles. Halley’s Comet is the most famous as it is a periodic comet. It appears in about every 76 years. In 1986, it was the last time when this comet was here and now it will appear in 2061.

Quick Facts: –

• This comet is named after an English astronomer Edmund Halley.
• He concluded that comets orbits the Sun and discovered this comet’s period of orbit.
• Halley examined the reports that said a comet approached the earth in 1531, 1607, 1682.
• Halley’s Comet is known as a short term comet because the time taken in orbiting the Sun is less than 200 years.
• A specific portion of this comet has a glowing appearance that is known as a coma. This coma is visible only when the comet is close enough to Sun.
• Length of this comet is around 9 miles.
• The Oort cloud is the origin of Halley’s Comet.
• This comet is estimated to be 4.5 billion years old.
• It is the first periodic comet to be identified.
• The first recorded appearance of this comet was in 240 B. C. as found in the Chinese Records of the Grand Historian.
• The direction of this comet’s orbit is opposite to the direction of planetary orbits.
• American writer Mark Twain was born in 1835, they same year in which the Halley’s Comet appeared and he made a successful prediction that he will die with a Halley’s Comet. Same thing happened as he died in 1910.

Atom

Atom

 An atom is the smallest possible piece of a chemical element. All matter is made of groups of atoms bonded, or connected, together into molecules.

The word atom comes from the Greek word “atomos,” which means “indivisible.”  Scientists used to think that atoms could not be broken up into smaller parts. But today, we know that they can. Atoms are made of smaller parts — protons, electrons and neutrons. Protons are particles with a tiny positive electrical charge. Neutrons have no electrical charge. And electrons have a tiny negative charge.

In an atom, the protons and neutrons hang out in the center, or nucleus. The electrons travel in a cloud around the nucleus. The cloud is split into layers called orbitals, where electrons are likely to be. Atoms of different elements have different numbers of protons, neutrons and electrons. The number of protons an atom has (its atomic number) determines which element it is.

The combination of protons, neutrons and electrons in an atom give each element its unique properties. For example, the four electrons in carbon’s outermost layer give this atom the ability to bond with up to four other atoms. This makes carbon an essential building block for every living thing on Earth. The 226 neutrons in radium-226 make this atom glow in the dark.

Because they are made of smaller particles, atoms can be broken up into pieces. Once that happens, though, the pieces are no longer a part of one chemical element. Break up a carbon atom, and you no longer have carbon. So a carbon atom is still the smallest possible piece of carbon.

Power words

atom: The basic unit of a chemical element. Atoms are made up of a dense nucleus that contains positively charged protons and uncharged neutrons. The nucleus is orbited by a cloud of negatively charged electrons.

atomic: Having to do with atoms, the smallest possible unit that makes up a chemical element.

atomic number: The number of protons in an atomic nucleus, which determines the type of atom and how it behaves.

bond: (in chemistry) A semi-permanent attachment between atoms — or groups of atoms — in a molecule. It’s formed by an attractive force between the participating atoms. Once bonded, the atoms will work as a unit. To separate the component atoms, energy must be supplied to the molecule as heat or some other type of radiation.

carbon: The chemical element having the atomic number 6. It is the physical basis of all life on Earth. Carbon exists freely as graphite and diamond. It is an important part of coal, limestone and petroleum, and is capable of self-bonding, chemically, to form an enormous number of chemically, biologically and commercially important molecules. (in climate studies) The term carbon sometimes will be used almost interchangeably with carbon dioxide to connote the potential impacts that some action, product, policy or process may have on long-term atmospheric warming.

chemical: A substance formed from two or more atoms that unite (bond) in a fixed proportion and structure. For example, water is a chemical made when two hydrogen atoms bond to one oxygen atom. Its chemical formula is H2O. Chemical also can be an adjective to describe properties of materials that are the result of various reactions between different compounds.

electron: A negatively charged particle, usually found orbiting the outer regions of an atom; also, the carrier of electricity within solids.

element: A building block of some larger structure. (in chemistry) Each of more than one hundred substances for which the smallest unit of each is a single atom. Examples include hydrogen, oxygen, carbon, lithium and uranium.

matter: Something that occupies space and has mass. Anything on Earth with matter will have a property described as "weight."

molecule: An electrically neutral group of atoms that represents the smallest possible amount of a chemical compound. Molecules can be made of single types of atoms or of different types. For example, the oxygen in the air is made of two oxygen atoms (O2), but water is made of two hydrogen atoms and one oxygen atom (H2O).

neutron: A subatomic particle carrying no electric charge that is one of the basic pieces of matter. Neutrons belong to the family of particles known as hadrons.

nucleus: Plural is nuclei. (in biology) A dense structure present in many cells. Typically a single rounded structure encased within a membrane, the nucleus contains the genetic information. (in astronomy) The rocky body of a comet, sometimes carrying a jacket of ice or frozen gases. (in physics) The central core of an atom, containing most of its mass.

orbital: Adjective for something relating to orbits. (in chemistry and subatomic physics) The pattern(s) of electrons (and their density) that form(s) within an atom or molecule.

particle: A minute amount of something.

proton: A subatomic particle that is one of the basic building blocks of the atoms that make up matter. Protons belong to the family of particles known as hadrons.

 

Let’s learn about colors

We live in a colorful world. Green leaves spring from the trees, flowers come in every color of the rainbow, and birds sport fashionably colorful feathers. We even live on a pale blue dot.

What creates all this color? Electromagnetic radiation — waves of energy moving through space. The waves come in different lengths. Cells in the backs of our eyes can perceive light as black, white, red, green or blue. The cells then relay that information to the brain — and we see the world in color. But we don’t see every color. Many wavelengths are beyond what humans can see.Nature has come up with many ways to make colors. Leaves, for instance, get their green from chlorophyll — the same chemical that helps them make sugar from sunlight. Some beetles, though, are beautifully shimmery from tiny structures in their wings. Those structures bounce light off differently at each angle, producing iridescence. And peacock spiders use a combination of pigments and tiny structures to get their beautiful behinds.

Power words

angle: The space (usually measured in degrees) between two intersecting lines or surfaces at or close to the point where they meet.

beetle: An order of insects known as Coleoptera, containing at least 350,000 different species. Adults tend to have hard and/or horn-like “forewings” which covers the wings used for flight.

birds: Warm-blooded animals with wings that first showed up during the time of the dinosaurs. Birds are jacketed in feathers and produce young from the eggs they deposit in some sort of nest. Most birds fly, but throughout history there have been the occasional species that don’t.

cell: The smallest structural and functional unit of an organism. Typically too small to see with the unaided eye, it consists of a watery fluid surrounded by a membrane or wall. Depending on their size, animals are made of anywhere from thousands to trillions of cells. Most organisms, such as yeasts, molds, bacteria and some algae, are composed of only one cell.

chemical: A substance formed from two or more atoms that unite (bond) in a fixed proportion and structure. For example, water is a chemical made when two hydrogen atoms bond to one oxygen atom. Its chemical formula is H2O. Chemical also can be an adjective to describe properties of materials that are the result of various reactions between different compounds.

chlorophyll: Any of several green pigments found in plants that perform photosynthesis — creating sugars (foods) from carbon dioxide and water.

electromagnetic: An adjective referring to light radiation, to magnetism or to both.

electromagnetic radiation: Energy that travels as a wave, including forms of light. Electromagnetic radiation is typically classified by its wavelength. The spectrum of electromagnetic radiation ranges from radio waves to gamma rays. It also includes microwaves and visible light.

hue: A color or shade of some color.

iridescent: Adjective that describes something that seems to change color with a shift in the angle at which it is viewed or at which lighting is applied.

pigment: A material, like the natural colorings in skin, that alter the light reflected off of an object or transmitted through it. The overall color of a pigment typically depends on which wavelengths of visible light it absorbs and which ones it reflects. For example, a red pigment tends to reflect red wavelengths of light very well and typically absorbs other colors. Pigment also is the term for chemicals that manufacturers use to tint paint.

radiant: (adj.) A term for something that is radiated, such as heat or some other type of radiation. (n.) The point or object from which light or heat radiates (such as the heating element in an electric heater). Or the point from which objects (such as meteors) appear to come.

radiation: (in physics) One of the three major ways that energy is transferred. (The other two are conduction and convection.) In radiation, electromagnetic waves carry energy from one place to another. Unlike conduction and convection, which need material to help transfer the energy, radiation can transfer energy across empty space.

robot: A machine that can sense its environment, process information and respond with specific actions. Some robots can act without any human input, while others are guided by a human.

spider: A type of arthropod with four pairs of legs that usually spin threads of silk that they can use to create webs or other structures.

wave: A disturbance or variation that travels through space and matter in a regular, oscillating fashion.

wavelength: The distance between one peak and the next in a series of waves, or the distance between one trough and the next. It’s also one of the “yardsticks” used to measure radiation. Visible light — which, like all electromagnetic radiation, travels in waves — includes wavelengths between about 380 nanometers (violet) and about 740 nanometers (red). Radiation with wavelengths shorter than visible light includes gamma rays, X-rays and ultraviolet light. Longer-wavelength radiation includes infrared light, microwaves and radio waves.

Electron

 Electron

This is one of the three types of particles that make up an atom. The other two are protons and neutrons. Protons and neutrons form the center, or nucleus, of an atom. Electrons exist in a surrounding cloud. They swarm around the center of the atom. That’s because electrons have negative electric charge. That makes them attracted to the positively charged protons in the nucleus. Normally, atoms have the same number of electrons as protons. So the atoms are electrically neutral.

Unlike protons and neutrons, electrons don’t contain smaller particles. That is, they are fundamental particles. Each electron is extremely small. Its mass is only about 1/1,800 the mass of a proton or neutron. Still, electrons play an important role in how atoms behave. Atoms of different elements hold their electrons in different arrangements around the nucleus. That arrangement gives each element its distinct properties. For instance, it determines how well an element conducts electricity. It also determines the temperature at which the element boils. And, that arrangement governs how likely atoms are to share electrons with each other. When atoms share electrons, they link together and form molecules.

Power words

atom: The basic unit of a chemical element. Atoms are made up of a dense nucleus that contains positively charged protons and uncharged neutrons. The nucleus is orbited by a cloud of negatively charged electrons.

cloud: A plume of molecules or particles, such as water droplets, that move under the action of an outside force, such as wind, radiation or water currents. 

electric charge: The physical property responsible for electric force; it can be negative or positive.

electron: A negatively charged particle, usually found orbiting the outer regions of an atom; also, the carrier of electricity within solids.

fundamental: Something that is basic or serves as the foundation for another thing or idea.

ion: (adj. ionized) An atom or molecule with an electric charge due to the loss or gain of one or more electrons. An ionized gas, or plasma, is where all of the electrons have been separated from their parent atoms.

link: A connection between two people or things.

mass: A number that shows how much an object resists speeding up and slowing down — basically a measure of how much matter that object is made from.

matter: Something that occupies space and has mass. Anything on Earth with matter will have a property described as "weight."

molecule: An electrically neutral group of atoms that represents the smallest possible amount of a chemical compound. Molecules can be made of single types of atoms or of different types. For example, the oxygen in the air is made of two oxygen atoms (O2), but water is made of two hydrogen atoms and one oxygen atom (H2O).

neutron: A subatomic particle carrying no electric charge that is one of the basic pieces of matter. Neutrons belong to the family of particles known as hadrons.

nucleus: Plural is nuclei. (in physics) The central core of an atom, containing most of its mass.

particle: A minute amount of something.

plasma: (in chemistry and physics) A gaseous state of matter in which electrons separate from the atom. A plasma includes both positively and negatively charged particles.

proton: A subatomic particle that is one of the basic building blocks of the atoms that make up matter. Protons belong to the family of particles known as hadrons.

INTRODUCTION to Physics

INTRODUCTION to Physics

 Without the science of physics and the work of physicists, our modern ways of living would not exist. Instead of having brilliant, steady electric light, we would have to read by the light of candles, oil lamps, or at best, flickering gaslight. We might have buildings several stories high, but there could be no hope of erecting an Empire State Building. We could not possibly bridge the Hudson River or the Golden Gate much less build a jet plane, use a cell phone, or watch a television show. The personal computer would be unimaginable.

All other natural sciences depend upon physics for the foundations of their knowledge. Physics holds this key position because it is concerned with the most fundamental aspects of matter and energy and how they interact to make the physical universe work. For example, modern physics has discovered how atoms are made up of smaller particles. It has also revealed how these particles interact to join atoms into molecules and larger masses of matter. Chemists use this knowledge to guide them in their work in studying all existing chemical compounds and in making new ones.

Biologists and medical researchers in turn use both physics and chemistry in studying living tissues and in developing new drugs and treatments. Furthermore their electrical equipment, microscopes, X-rays, and many other aids and the use of radioactivity were developed originally by physicists.

Physicists have also led in bringing people to think in scientific ways. What we call the scientific method had its real beginnings some four centuries ago in many fields of knowledge. The most impressive of the early triumphs came in physics and in its application to astronomy for studying the motions of the Sun, Moon, planets, and stars.

Galileo made the first real contributions, in the late 16th and early 17th century. He discovered the natural laws that govern falling bodies and the swinging of the pendulum. Shortly after this, Johannes Kepler established the three laws that explain all the motions of the planets. Finally, in the late 17th century Isaac Newton explained these results by establishing the law of gravitation. This law applies invariably to all matter in the universe—whether it is as small as a grain of sand or as large as the Sun. This triumph of explaining a vast range of phenomena with a single law inspired workers in all fields of knowledge to trust scientific methods.

This revolution in understanding was greatly aided by concurrent advances in technology. Instruments such as clocks, barometers (which measure the pressure of the atmosphere), and telescopes were invented and improved. For example, Galileo, Kepler, and Newton made contributions to the development of telescopes and thus gave astronomy a powerful instrument with which to work.

There is no exact distinction between physics and other natural sciences because all sciences overlap. In general, however, physics deals with phenomena that pertain to all classes of matter and energy. Physicists try to discover the most basic laws of nature, which underlie and often explain those of other fields of science.

One major branch of physics, mechanics, deals with the states of matter—solids, liquids, and gases—and with their motions. The pioneer achievements of Galileo, Kepler, and Newton dealt with solid masses of matter in motion. Such studies are a part of the subdivision of mechanics called dynamics, the study of matter in motion. This wide-ranging topic includes not only the motions of stars and baseballs but also those of gyroscopes, of the water pumped by a fire engine (hydrodynamics), and of the air passing over the wings and through the jet engine of an airplane (aerodynamics).

The other great subdivision of mechanics is statics, the study of matter at rest. Statics deals with the balancing of forces with appropriate resistances to keep matter at rest. The design of buildings and of bridges are examples of problems in statics.

Other divisions of physics are based on the different kinds of energy that interact with matter. They deal with electricity and magnetism, heat, light, and sound. From these branches of physics have come clues that have revealed how atoms are constructed and how they react to various kinds of energy. This knowledge is often called the basis of modern physics. Among the many subdivisions of modern physics are electronics and nuclear physics.

Physics is closely related to engineering. A person who uses physical principles in solving everyday problems is often called an engineer. For example, electricity is one of the subdivisions of physics; one who uses the natural laws of electricity to help in designing an electric generator is an electrical engineer.

Newton's 3 Laws of Motion for Kids: Three Physical Laws of Mechanics for Children - FreeSchool