Depiction of Experiments to Show Physical Changes

We see a lot of changes around us on a regular basis and they can be classified under physical and chemical changes. These changes have different features and properties and can affect our basic understanding and knowledge of the field of Chemistry. Here, let us try to understand more about physical changes, what they are, how to identify them and their basic features.

What are Physical Changes?

A physical change is one where there are changes only in the physical properties of the components. For example, when a pure gold ingot is melted, then it changes from solid gold to liquid gold. However, there is no change in the chemical composition of the component, which is gold, in case of physical changes. 

In the example of the gold ingot, the observed changes are listed below:

1. The solid gold ingot changes to liquid form. Cooling it back will help the gold retain its solid form again, though there be changes in its shape.
2. The temperature of the liquid gold is quite high, and it can be reversed back to its original temperature by cooling it.
3. The shape of the solid ingot changes when it is liquified. Using proper methods of shaping and casting while cooling the liquid gold can help get back the original shape. 

These are all changes in the physical properties of the material and no chemical change takes place. 

How to Identify a Physical Change?

Sometimes, identifying and classifying a change as a physical change might seem difficult and seemingly impossible. The following pointers can help you understand whether a change is physical or chemical in nature.

1. In most cases, a physical change is reversible in nature. However, changes which involve breaking and physical deformation might be irreversible under normal circumstances. They can also be turned back to their original form using sophisticated recycling and reformation techniques.
2. If there is a color change or evolution of gas bubbles, the change might no longer be physical in nature. 
3. If the product formed has completely different properties as compared to its constituents, it is no longer a physical change. In physical changes, the chemical composition of the constituents remains the same and the product would be able to exhibit the properties of the parent constituents.

Some Easy Physical Change Experiments

There are quite a few easy experiments that you can carry out at home or in your school lab to understand physical changes better. Here are five easy physical change experiments that you can try out. 

• Dissolving Salt in Water

Dissolving salt in water is a physical change. It becomes a homogeneous mixture on complete dissolution, but there is no change in the chemical composition of salt and water. In fact, using physical methods like distillation, we can even get back the individual components, namely salt and water.

• Melting Ice

The melting of ice into water is an easy experiment to exhibit physical change. Here, ice changes from the solid state to its liquid state. This is a reversible change, and water can be turned back into ice by lowering its temperature.

• Mixing Water and Oil

Since oil and water do not react, this is a physical change. Furthermore, the components of this heterogeneous mixture can be separated using physical separation methods. 

• Giving Shape to Clay

Giving shape to clay is a physical change experiment that can be tried out at home very easily. Once given a shape, you can even choose to change its shape back to its original form. Even if clay hardens, it can be softened with water and there is no chemical change involved in the process. 

• Folding Paper

Folding paper is an example of physical change. Once you fold paper, it might be difficult to get back the original shape and structure of the paper. This shows that not all physical changes are reversible. 

Conclusion

As you now know what physical changes are, you should be able to recognize them easily. Physical changes are reversible in most cases, so you would be able to turn the component back to its original state quite easily. Being able to recognize changes can be very helpful for understanding basic chemistry, which forms the basis of more advanced concepts.