Facts At Your Fingertips: Matter and materials – Reactions and changes Physical changes occur when substances change state. Chemical reactions occur when the atoms in molecules are rearranged to create different molecules. Changes caused by physical reactions are usually easy to reverse, while chemical changes are not. Chemical reactions These reactions can be caused by … Read more
Facts At Your Fingertips: Matter and materials – Mixtures and compounds Different elements can be combined to create new substances. When atoms and molecules chemically combine to form a substance, it is called a compound. If no chemical reaction takes place—as when mud is added to water—a mixture is formed. Compounds These are often very … Read more
Facts At Your Fingertips: Matter and materials – Elements A chemical that is made up of atoms of just one type is known as an element. Although all atoms are made of the same basic parts—protons, neutrons, and electrons—not all atoms are the same. It is the number of these parts that gives the atom—and … Read more
Facts At Your Fingertips: Matter and materials – Molecules Most atoms do not exist on their own, but bond with other atoms—either ones of their own type or of another element—to form molecules. Atoms join together by sharing their electrons, a process known as chemical bonding. Simple molecules The natural state of oxygen is nearly … Read more
Facts At Your Fingertips: Matter and materials – Atoms Atoms are the tiny building blocks that make up everything in the universe, including ourselves. They are far too small to be seen, even with the most powerful microscopes. Billions of them could fit on the dot of this “i.” Yet atoms are themselves made up … Read more
Facts At Your Fingertips: Matter and materials – Properties of matter Different substances have different properties. They might be hard or soft, flexible or rigid, flammable or not. Testing the properties of a particular substance helps in determining what it can, and cannot, be used for. Mass and density The amount of matter within an … Read more
Facts At Your Fingertips: Matter and materials – The water cycle Earth’s water is constantly changing state as it circulates between the sea, the land, and the sky. This process is known as the water cycle. Although water is always moving, the total amount of water in the world always stays exactly the same. Water … Read more
Pocket Genius Science: Matter and materials – States of matter Matter is everywhere, but you cannot always see it. There are four main types, or states, of matter—solid, liquid, gas, and plasma. Each state is made up of moving particles, but they look and behave very differently. Solids In solids, the particles are packed together … Read more
Facts At Your Fingertips: Matter and materials Everything on Earth is made from different types of matter, which behave in different ways, depending on the conditions. Rock, for example, can form solid mountains, but at high temperatures it melts and flows as lava. Exploring the way matter changes its form under different conditions of heat … Read more
Pocket Genius Science – Everyday science Science does not just take place in laboratories. It forms part of almost everything we do, whether it is cooking food, playing with plastic toys, speaking to a friend on the telephone, surfing the Internet, or traveling from one place to another. Play From plastic toys and computer games … Read more
