Introduction of Physical Change

Have you ever noticed the  boiling/freezing of water, melting of an ice cube, dissolution of sugar or salt in water, burning of coal, souring of milk, rusting, etc.? 

Ever thought about why and how these changes could occur? 

What is the scientific reason behind them? 

All these are changes in a substance. We can classify them as physical or chemical changes depending on the type of process involved during transformation. This article gives a brief introduction of physical change.

Physical Change

As mentioned properties such as weight, size, density, colour, odour, height, volume, appearance all are physical properties. Any change in a substance leading to alteration of these physical properties is called physical change. 

The physical change only affects the physical appearance of a substance, that is, it does not affect the chemical properties of a substance. For example, when ice melts, it gets converted into liquid water. In this case, only the state of matter (liquid) changes, not the chemical properties of water.

A substance undergoes a physical change when its compound creation is unaffected.

A physical exchange entails a change in physical properties. Examples of physical properties include melting, transition to a gas, exchange of strength, trade of durability, adjustments to crystal form, textural change, shape, size, colour, quantity, and density.

Generally, many chemical adjustments are irreversible, whereas many physical changes are reversible. However, reversibility cannot be the only criterion for classification. 

Although chemical adjustments may be diagnosed by means of an indication, such as odour, colour change, or production of a gas, every one of these warning signs can end result from the physical change.

Characteristics of a Physical Change

Few properties help in distinguishing the physical changes from chemical ones. These features are as below:

• There is no new substance formation.

Whenever a substance undergoes physical change, it never produces a new substance. 

For instance, consider a 100g of ice cube in a glass. When kept at room temperature for some time, it will convert to an equivalent amount of water. This behaviour indicates the conversion of state of matter from solid to liquid.

• Physical changes that involve a change of state are all reversible. 

As the name suggests, we can easily revert these changes.

Let us consider the previous example again. We can freeze the water at the proper temperature to transform it back to ice. So physical changes are always reversible.

• The chemical properties of substances don’t change.

The chemical properties of a substance remain unaffected regardless of physical change. 

For example, origami crafts made with paper only change the shape of the paper, not the chemical properties of paper.

• Energy formation or evolution does not take place. 

In physical processes, there is no absorption or evolution of energy. It means there is no production of any form of energy like heat, sound, chemicals etc. So, there is no liberation of energy.

Key Terms and Facts

• Changes in any substance occur due to various internal and external influences.
• Physical as well as chemical processes are two types of changes that occur around us.
• Physical changes are the changes to a substance’s physical attributes, such as form, size, shape, and states. These alterations result in the formation of no new compounds. These changes might as well be reversible. 
• A phase change is regarded as a change in the form of matter, often known as a physical change.
• Liquid water turning to solid ice or going through evaporation to form water, the gaseous state of water, are both examples of physical changes.
• Boiling as well as evaporation are examples of phase transitions.
• Chemical changes are the changes that alter the chemistry including composition or structure of a substance.
• Several new chemicals are produced during chemical reactions, for instance, rusting, ozone generation in the environment, etc.
• A chemical change might accompany heating, light or gas emissions, sound creation, a transition in smell or colour, etc., in the form of new products.
• If we want to extract a metal from an ore, like iron from iron ore, we must undergo a chemical transformation sequence. Likewise, medicine is the result of a series of chemical processes. Chemical reactions provide essential new substances such as polymers and cleansers.

Difference Between Physical and Chemical Changes

The difference between the physical and chemical changes are as follows:

Conclusion

From the topic discussed above, we can conclude that many changes are always taking place all around us. There are a few ways in which a substance’s shape, size, or physical properties can change. Physical attributes are a substance’s traits such as size, shape, colour, and physical  state.

There are no new resources generated at some point of a Physical Change, and most physical changes are reversible.