Light also transfers energy from place to place.
The amount of matter is conserved when it changes form, even in transitions in which it seems to vanish.
The expression “produce energy” typically refers to the conversion of stored energy into a desired form for practical use.
Waves of the same type can differ in amplitude (height of the wave) and wavelength (spacing between wave peaks.)
Digitalized information can be transmitted over long distances without significant degradation. High-tech devices, such as computers or cell phones, can receive and decode information—convert it from digitalized form to voice – and vice versa.
The gravitational force of Earth acting on an object near Earth’s surface pulls that object toward the planet’s center.
When objects collide, the contact forces transfer energy so as to change the objects’ motions.
When two or more different substances are mixed, a new substance with different properties may be formed.
Electric and magnetic forces between a pair of objects do not require that the objects be in contact. The sizes of the forces in each situation depend on the properties of the objects and their distances apart and, for forces between two magnets, on their orientation relative to each other.
An object can be seen when light reflected from its surface enters the eyes.
Waves, which are regular patterns of motion, can be made in water by disturbing the surface. When waves move across the surface of deep water, the water goes up and down in place; there is no net motion in the direction of the wave except when the water meets a beach.
Energy is present whenever there are moving objects, sound, light, or heat. When objects collide, energy can be transferred from one object to another, thereby changing their motion. In such collisions, some energy is typically also transferred to the surrounding air; as a result, the air gets heated and sound is produced.
Energy can also be transferred from place to place by electric currents, which can produce motion, sound, heat, or light. The currents may have been produced to begin with by transforming the energy of motion into electrical energy.
The energy released from food was once energy from the sun that was captured by plants in the chemical process that forms plant matter (from air and water).
Objects in contact exert forces on each other.
Energy can be moved from place to place by moving objects or through sound, light, or electric currents.
Matter of any type can be subdivided into particles that are too small to see, but even then the matter still exists and can be detected by other means. A model showing that gases are made from matter particles that are too small to see and are moving freely around in space can explain many observations, including the inflation and shape of a balloon and the effects of air on larger particles or objects.
No matter what reaction or change in properties occurs, the total weight of the substances does not change.
Measurements of a variety of properties can be used to identify materials.
Each force acts on one particular object and has both strength and a direction. An object at rest typically has multiple forces acting on it, but they add to give zero net force on the object. Forces that do not sum to zero can cause changes in the object’s speed or direction of motion.
The patterns of an object’s motion in various situations can be observed and measured; when that past motion exhibits a regular pattern, future motion can be predicted from it.
The faster a given object is moving, the more energy it possesses.