Facts At Your Fingertips: Energy and forces – Sound Sounds are vibrations that we hear with our ears. The vibrations travel through substances such as air or water in the form of sound waves. When the waves reach our ears, they make our eardrums vibrate. The size and shape of the waves determine the kind … Read more
Facts At Your Fingertips: Energy and forces – Heat The atoms and molecules that make up matter are always on the move. The more energy they have, the faster they move. We feel this energy as heat. Heat will always move from a warmer area to a colder one until both areas are the same … Read more
Facts At Your Fingertips: Energy and forces – Radioactivity In some atoms, the nucleus changes over time, releasing particles and energy, known as radiation. This process is called radioactive decay. We encounter low-level radiation all the time—in the soil, in the air, and in the food we eat. Types of radioactivity There are three types … Read more
Facts At Your Fingertips: Energy and forces – Using light We need light to see the world and to find our way around it. In the earliest days of humanity, we just used the natural light produced by the Sun and went to bed when it got dark. Today, we can also use artificial lights … Read more
Facts At Your Fingertips: Energy and forces – Light Light is the only form of electromagnetic radiation we can see. Most things absorb and reflect light, but few objects give out light. The Sun is the main source of light in the day, while electric lights provide illumination at night. Making shadows Some materials, such … Read more
Facts At Your Fingertips: Energy and forces – The EM spectrum Electromagnetic (EM) radiation is a form of energy that travels in waves at a speed of 186,000 miles (300,000 km) per second, which is the fastest speed in the universe. Different kinds of radiation make up the EM spectrum. All types of radiation except … Read more
Facts At Your Fingertips: Energy and forces – Electromagnetism An electrical current always produces a magnetic field around it. Electromagnets are made by passing electricity through a wire that has been wrapped around a piece of iron. Unlike permanent magnets, an electromagnet loses its magnetism as soon as the electrical current is switched off. How … Read more
Facts At Your Fingertips: Energy and forces – Magnets in action We use magnets in many different ways. The motors inside many machines are driven by small magnets, while large magnets can power trains. Compasses use Earth’s magnetism to show us the way. Electric motors This toy car is powered by an electric motor, which … Read more
Facts At Your Fingertips: Energy and forces – Magnetism Magnetism is a force that can attract (pull toward) or repel (push away). Materials that are strongly attracted to magnets, such as iron or nickel, are called ferromagnetic materials. Some magnets are permanently charged with magnetism, while others are only magnetic when they are inside a … Read more
Facts At Your Fingertips: Energy and forces – Using electricity The electricity we use around our homes and to power our gadgets is produced in several ways. It can be generated in massive power plants located far away. On a smaller scale, items such as flashlights and cell phones can be powered by batteries that … Read more
