Physical changes are those that alter the appearance or shape of a substance, without changing its chemical properties. These changes can occur in solids, liquids, and gases. Examples of physical changes include melting, freezing, evaporating, condensing, sublimation and deposition.
One example of a physical change is when ice melts into water. When heat is applied to ice at 0 degrees Celsius it begins to break down the solid structure which allows the particles to move about more freely. As a result, the bonds between molecules weaken and eventually break apart causing them to separate and form liquid water. This process occurs without any chemical reaction taking place and as such is considered a physical change.
Another example of a physical change is when iron rusts over time due to exposure from moisture in the air.
Physical changes are changes that affect the physical properties of a substance or material, but do not alter its chemical composition. In other words, the substance remains the same, but its appearance, state, or form changes. Physical changes can be reversible or irreversible, and they are common in our daily lives. Here are some examples of physical changes:
Change in State
When a substance changes its state from solid to liquid, or from liquid to gas, it undergoes a physical change. For example, when you heat ice, it melts and becomes water. The water is still H2O, but its physical form has changed. Similarly, when you boil water, it turns into steam. The steam is still water, but it has changed from liquid to gas.
Change in Shape or Size
When a substance changes its shape or size, it undergoes a physical change. For example, when you cut a piece of paper into smaller pieces, the paper has changed its shape and size, but it is still paper. Similarly, when you inflate a balloon, the balloon changes its size and shape, but it is still made of the same material.
Change in Texture or Appearance
When a substance changes its texture or appearance, it undergoes a physical change. For example, when you crumple a piece of paper, it changes its texture and appearance, but it is still paper. Similarly, when you shave a block of soap, it changes its texture and appearance, but it is still soap.
When two or more substances are mixed together, they undergo a physical change. For example, when you mix salt and water, the salt dissolves in the water and forms a solution. The salt is still NaCl, and the water is still H2O, but they have changed their physical state and properties.
Physical changes are common in our daily lives, and they affect the physical properties of substances without altering their chemical composition. Understanding physical changes is important in many fields, such as chemistry, physics, and engineering. By knowing how physical changes occur, we can better understand the world around us.