SomeFacts | Science

Science

No one is sure. Atoms are made of protons, neutrons and electrons. In ...

Since the 1920s, scientists have discovered that there are at least ...

Electrons can be split off from atoms easily, but in 1919, the New ...

An ion is an atom that has either lost one or a few electrons, making ...

Most of an atom is empty space, but right at its center is a very ...

Electrons are held to the nucleus by electrical attraction - because ...

Electrons are the very tiny electrically charged particles that whizz ...

Quite often, atoms cannot exist by themselves, and must always join ...

Atoms are about a ten millionth of a millimeter across and weigh 100 ...

If you squeeze a gas into half the space, the pressure doubles (as ...

Pressure is the amount of force pressing on something. Air pressure ...

Things melt from solid to liquid on reaching a temperature called the ...

Things boil from liquid to gas when they reach boiling point, which ...

Things freeze from liquid to solid when they reach the freezing ...

A plasma is the rare fourth state of matter. It occurs only when a ...

Mercury has the lowest freezing point of any metal -38.87°C ...

The metal with the highest melting point is tungsten, which melts at ...

The lightest element is hydrogen. It has just one proton in its ...

The lanthanides are a group of 15 elements in the middle of the ...

Atomic mass is the 'weight' of one whole atom of a substance - which ...

The Polish-French physicist Marie Curie (1867-1934), born Marya ...

Carbon is the most friendly element in the Universe. With four ...

Elements are reactive if they readily gain or lose electrons. ...

Group 0 is the furthest right-hand column of the periodic table. This ...

Most people can recognize a metal. It is hard, dense and shiny, and ...

Transition metals are the metals in the middle of the periodic table, ...

The heaviest is hahnium. It has 105 protons and 157 neutrons in its ...

New elements are discovered every so often, but the total number ...

Pure air is 78.9% nitrogen, 20.95% oxygen. There are traces of argon ...

The sea is water with oxygen, carbon dioxide, nitrogen and various ...

A chemical formula is a shorthand way of describing an atom, an ion ...

Mixtures are substances that contain several chemical elements or ...

Electrolysis is a chemical reaction caused when an electric current ...

Batteries create electric currents from the reaction between two ...

When an object is immersed in water, the weight of the object pushes ...

No-one can predict when an atomic nucleus will decay. But scientists ...

The first atomic bombs were developed in the USA towards the end of ...

Radioactivity proceeds at a very steady rate. So by measuring how ...

It causes radiation sickness. With a very high dose, the victim dies ...

Inside the reactor there are fuel rods made from pellets of uranium ...

An atomic bomb or A-bomb is one of the two main kinds of nuclear ...

Nuclear fission releases nuclear energy by splitting big atomic ...

Nuclear energy is released by fusing or joining together small atoms ...

When solids dissolve in liquid, it may look as if the solid ...

Cellulose is a natural fiber, found in the walls of all plant cells. ...

Oil drilled from the ground, called crude oil, is separated into ...

Polymers are substances made from long chains of thousands of small ...

The discovery in 1953 that every molecule of DNA is shaped like a ...

Before 1990, carbon was known in two main forms or allotropes ...

Nobody knows for sure, but wheels turned by water to generate power ...

Hydroelectric power or HEP is electricity generated by turbines ...

Because sweat is nearly all water, and water needs warmth to turn to ...

Plants contain an even higher proportion of water than the human ...

Water is found in nearly every cell of the body, which is why human ...

Heavy water is deuterium oxide - water that is a little heavier than ...

Fluids like water are incompressible - that is, they cannot be ...

Light, which travels at 300,000 km (186,000 miles) per second. This ...

Albert Einstein (1897-1955) was the scientific genius who transformed ...

The theory of Special Relativity shows how both space and time can be ...

Speed is how fast something is going. Velocity is how fast something ...

Uniform motion is when an object carries on travelling at exactly the ...

When something fixed in one place, called a fulcrum, is pushed or ...

When two objects collide, their combined momentum remains the same, ...

This is Newton's Third Law of Motion for every action, there is an ...

Acceleration is how fast something gains speed. The larger the force ...

Inertia is the tendency of things to stay still unless they are ...

Sir Isaac Newton's breakthrough, in 1665, was to realize that all ...

Carbohydrates are chemicals made only of carbon, hydrogen and oxygen ...

Carbon circulates like this: animals breathe out carbon as carbon ...

Benzene is a clear liquid organic chemical found in coal tar. It can ...

Carbon atoms often link together like the links of a chain to form ...

Most plastics are made from ethene, one of the products of cracked ...

Oils are thick liquids that won't mix with water. Mineral oils used ...

Oil is formed from tiny plants and animals that lived in warm seas ...

Satellites are whizzing through space at exactly the right height for ...

An object's gravitational pull varies with its mass and its distance. ...

The Moon is much smaller than the Earth, so its gravity is much ...

At first, the stone falls faster and faster at a rate of 9.8 metres ...

Friction is the force between two things rubbing together, which may ...

Force is measured in newtons, in honor of Sir Isaac Newton. A newton ...

The mathematician and physicist Sir Isaac Newton is said to have ...

The Italian scientist and astronomer Galileo Galilei (1564-1642) is ...

Gravity is the invisible force of attraction between every bit of ...

Power is the rate at which work is done - a high-powered engine is an ...

Mass is the amount of matter in an object. It is the same wherever ...

An echo is when you shout in a large empty hall or in a tunnel, and ...

Some sounds, like a car's squealing brakes, are very high-pitched. ...

If allowed to vibrate freely, every object always tends to vibrate at ...

As the Earth spins, the swirling of its iron core turns the core into ...

Thousands of years before people learned how to make steel magnets, ...

The magnetic field is the area around the magnet in which its effects ...

An electric bulb has a very thin filament of tungsten wire inside a ...

A direct current (DC) flows in one direction only. Most hand-held ...

Not all substances conduct electric currents equally well. Resistance ...

Electrical current flows as long as there is a difference in charge ...

Transistors were invented by three scientists working at the Bell ...

Semi-conductors are materials such as silicon or germanium, which are ...

The best conductors are metals like copper and silver. Water is also ...

The charge in an electric current is electrons that have broken free ...

A silicon chip is an electronic circuit implanted in a small crystal ...

A current is a continuous stream of electrical charge. It happens ...

Italian inventor Guglielmo Marconi first sent radio signals over 1.6 ...

TV signals travel in one of three ways. Terrestrial broadcasts are ...

CT (computed tomography) scans run X-ray beams right round the body, ...

X-rays are stopped only by the bones and especially dense bits of the ...

Infrared is light with wavelengths too long for the human eye to ...

Prisms split white light into separate colors by refracting (bending) ...

Ultraviolet light is light with wavelengths too short for the human ...

When scientists talk about reflections, they distinguish between the ...

Sunlight is white - which means it contains all the colors of the ...

When light rays hit a surface, some bounce off, but others are ...

Photons are almost infinitesimally small particles of light. They ...

In the last century, most scientists believed light did travel in ...

Most mirrors are made of ordinary glass, but the back is silvered ...

The sun is only red at sunrise and sunset, when the sun is low in the ...

Actually they don't bend light, but reflect it round comers. Inside a ...

Light rays are bent when they are refracted. This happens when they ...

Temperature is usually measured with a thermometer. Some thermometers ...

You can convert from Fahrenheit to Celsius by subtracting 32 then ...

Heat is molecules moving. It is a form of energy the combined energy ...

Conduction is one of the three ways in which heat moves. It involves ...

Absolute zero is the coldest possible temperature, the temperature at ...

Energy is a form of mass; mass is a form of energy. In nuclear ...

Some machines waste a great deal of energy, while others waste very ...

Energy can be neither created nor destroyed. When energy is converted ...