How do we measure temperature?

Temperature is a measurement of the amount of heat that is stored in an object. It is measured against a scale in either degrees Celsius (°C) or degrees Fahrenheit (°F) on a thermometer....

Where does the Earth's energy come from?

There is a basic law of physics that says that energy is never created or destroyed; it is simply transferred from one place to another or from one form of energy to another. So...

How fast does light travel?

The speed of light is the fastest speed known - light travels through the vacuum of space at 300,000 km per second. Nothing else can travel at this speed, and the theory of relativity...

What is light?

Light is a form of electromagnetic energy. It is produced by electrons that have gained extra energy from another source. This energy can be given off as heat or light. Light travels...

What are acids?

Bee stings are acidic. An acid is neutralized by an alkali, so to reduce the painful effects of a bee sting, soap, which is alkaline, should be applied. Acids are a group of chemicals...

What happens when iron rusts?

The reddish powdery rust that forms on unprotected iron and steel is the result of a process called oxidation. It takes place when the metal reacts with oxygen from the air and water....

What is evaporation?

Evaporation happens when a liquid or a solid changes to a gas. It is a similar process to boiling, because it involves the molecules of a liquid passing into the air. The process of...

What happens when a liquid boils?

When a liquid is heated, at a certain point it begins to change to a gas, or vapour. This happens because at high temperatures the molecules in the liquid move faster, until they escape...

What are plastics?

Plastics are synthetically produced materials that are capable of being moulded and made into useful shapes such as bottles and flat sheets. They usually soften under heat and pressure...

What happens when a chemical substance dissolves?

When sugar is stirred into water, it dissolves and forms a solution. This means that the solid sugar molecules have split apart and become distributed equally throughout the water,...

How are crystals formed?

Crystals are solid substances that have their atoms arranged in regular patterns. Most naturally occurring substances form crystals under the right conditions, although they are not...

What is glass?

Glass forms when melted solid materials are cooled quickly, so that they do not produce crystals. There are many types of glass, but the transparent glass that is most familiar to us...

Quicksilver

Mercury is the only metal that is a liquid at ordinary room temperatures. It is a bright shiny color, and flows rapidly when poured out of a container (this is why it used to be called...

What are gases?

Matter exists in three states: solid, liquid and gas. The molecules in all matter are in constant motion, and in a gas they are held together so loosely that they can move freely. Gas...

How is it possible to make new elements?

New elements are created by bombarding other elements with radiation in an atomic reactor. Scientists have made 16 artificial elements by bombarding uranium and other radioactive elements. Many...

What is radioactivity?

Radioactivity is a form of energy given off by some types of atom with a high atomic number, such as uranium, radium and plutonium. Some forms of radiation consist of protons and neutrons...

What is the periodic table?

The periodic table is a list of all the elements, arranged in such a way that elements with similar properties are grouped together. Each element in the table is given a number, called...

What is antimatter?

Antimatter is like normal matter, but it is made up of particles that are exactly the 1 opposite to those making up ordinary matter. A normal electron, for example, has a negative charge...

What are molecules?

The smallest part of a substance that can exist on its own is a molecule. This consists of anything between two and several thousand atoms, which are linked together by chemical bonds....

What is Quantum mechanics?

Quantum mechanics helps us to understand how energy is used or released by atoms. Negatively charged electrons circle about the positively charged nucleus of the atom. They stay in...

What are electrons?

Electrons are the very tiny particles that travel around the nucleus of an atom at incredibly high speed. They carry a negative electrical charge. The circling electrons are arranged...

Is an atom the smallest type of particle?

There are many smaller particles, and more are being discovered. These very small particles are known as subatomic particles. The electron revolving around the atom, and the neutron...

Can we see atoms?

Atoms are the smallest pieces of matter. They are the tiniest particles into which a substance can be divided without changing into something else. Atoms actually consist almost entirely...

Who found a land route from Europe to China?

The first famous European traveller was Marco Polo, a Venetian merchant who travelled to China in the 13th century. He met the Chinese emperor, Kublai Khan, and travelled widely throughout...