Facts At Your Fingertips: Matter and materials – Using materials Throughout history, people have used and reused materials. Many natural substances can be adapted or changed to produce new substances. For example, soft clay can be turned into hard pottery, sand can be transformed into glass, and iron and carbon can be combined to form … Read more
Facts At Your Fingertips: Matter and materials – Acids and bases Acids and bases are chemical opposites: acids produce positively charged hydrogen ions and bases produce negatively charged hydroxide ions. Many acids and bases can be combined to produce useful substances, such as salts and soaps. Acids Some powerful acids are very corrosive, which means … Read more
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
Facts At Your Fingertips: Matter and materials – Changing states A substance may not always remain in the same state of matter. It can change state when it is at different temperatures. For example, a solid can become a liquid if it becomes hot enough and a liquid may become a solid if it is … Read more
