Or it can mean changing the substance itself, turning it into something else, for example smelting metal ores to extract pure metal. Gases such as air are the lightest state of matter. They are easy to push through, and may not be visible to human eyes. The particles in a gas are not connected to each other, so they can float around freely. Solids, such as wood and stone, have a fixed shape that is difficult to change.
This is because the particles inside them are linked to each other and fixed in place. Liquids such as water can flow freely, changing their shape. This is because the particles that make up a liquid are not fixed in place. They stay linked together, but can move around each other. Some matter is bound up in living creatures, such as animals and plants. It is important to understand the particle nature of matter.
The physical characteristics of those atoms and molecules decide its state. Something is usually described as a solid if it can hold its own shape and is hard to compress squash. The molecules in a solid are closely packed together — they have a high density.
Right now, you are probably sitting on a chair, using a mouse or a keyboard that is resting on a desk — all those things are solids. In liquids , the molecules have the ability to move around and slide past each other.
A liquid will take on the shape of the container it is being held in. While a liquid is easier to compress than a solid, it is still quite difficult — imagine trying to compress water in a confined container! In gases, the atoms are much more spread out than in solids or liquids, and the atoms collide randomly with one another. A gas will fill any container, but if the container is not sealed, the gas will escape.
Gas can be compressed much more easily than a liquid or solid. Right now, you are breathing in air — a mixture of gases containing many elements such as oxygen, nitrogen and carbon. Plasma is very similar to gas, In fact, the easiest way to describe plasma is as a gas that can carry an electrical charge. Plasma is a form of matter that exists when atoms are in an excited state. They are so excited that they jump an energy level and, in doing so, give off light.
Plasma particles are spread out and move around randomly, but unlike gas, they contain some free ions and electrons, which gives plasma its ability to conduct electricity.
Since there is almost no kinetic energy being transferred from one atom to another, the atoms begin to clump together.
There are no longer thousands of separate atoms, just one "super atom. A BEC is used to study quantum mechanics on a macroscopic level. A BEC also has many of the properties of a superfluid , or a fluid that flows without friction. BECs are also used to simulate conditions that might exist in black holes. Adding or removing energy from matter causes a physical change as matter moves from one state to another.
For example, adding thermal energy heat to liquid water causes it to become steam or vapor a gas. And removing energy from liquid water causes it to become ice a solid.
Physical changes can also be caused by motion and pressure. When heat is applied to a solid, its particles begin to vibrate faster and move farther apart. When the substance reaches a certain combination of temperature and pressure, its melting point , the solid will begin to melt and turn into a liquid. When two states of matter, such as solid and liquid, are at the equilibrium temperature and pressure, additional heat added into the system will not cause the overall temperature of the substance to increase until the entire sample reaches the same physical state.
For example, when you put ice into a glass of water and leave it out at room temperature, the ice and water will eventually come to the same temperature. As the ice melts from heat coming from the water, it will remain at zero degrees Celsius until the entire ice cube melts before continuing to warm. When heat is removed from a liquid, its particles slow down and begin to settle in one location within the substance. When the substance reaches a cool enough temperature at a certain pressure, the freezing point, the liquid becomes a solid.
Most liquids contract as they freeze. Water, however, expands when it freezes into ice, causing the molecules to push farther apart and decrease the density, which is why ice floats on top of water. Adding additional substances, such as salt in water, can alter both the melting and freezing points.
For example, adding salt to snow will decrease the temperature that water freezes on roads, making it safer for drivers.
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