Matter in Our Surroundings Class 9 Science

Name one thing that can be classified as matter according to the teacher.

Anything that occupies space, like a book or a table.

What is an example of something that is not considered matter?

Emotions, thoughts, or sound.

According to early classification, what are the basic elements matter is made of?

Earth, water, fire, air.

What is diffusion?

The intermixing of particles on their own.

How does temperature affect the rate of diffusion?

Higher temperature increases the rate of diffusion.

What happens to a solid when it is heated?

It can change into a liquid, a process known as melting or fusion.

What is the difference between evaporation and boiling?

Evaporation is a surface phenomenon occurring at any temperature; boiling occurs throughout the liquid at its boiling point.

What are three states of matter discussed in the lecture?

Solids, liquids, and gases.

What do we call the temperature at which a solid melts into a liquid?

Melting point.

What is sublimation?

The process of a solid changing directly into a gas without becoming a liquid.

Provide an example of a substance that undergoes sublimation.

Dry ice (solid carbon dioxide).

What causes the cooling effect when volatile liquids evaporate?

Evaporation takes heat from the surface, causing a cooling sensation.