Maharashtra Board Class 5 EVS Part I Chapter 24 Substances Objects and Energy PDF Download

Substances, Objects and Energy

Can You Tell?

Write a few lines on the blackboard with a chalk. Now observe the chalk.

What change do you see in the chalk? Wipe the board with a duster and then tap the duster against the table. What do you see?

The chalk has become smaller and when the duster was tapped, particles of chalk fell off from it. These particles were of the same colour as the piece of chalk. This tells us that when you wrote on the board, particles of the chalk stuck to the board and when you wiped the board, they came off.

Try This

Take small pieces of candy sugar or coal and pound them in a mortar.

What do you notice?

When you pound the coal or the sugar, it turns into a powder, that is, into small particles.

All substances we see around us are made up of very tiny particles. You must have seen how sawdust or particles of wood fly when the wood is cut with a saw.

When iron or copper is made smooth with a file, we get particles of iron or copper. All substances like pencil, chalk, paper, wood, wheat grains, iron, copper, coal are all made up of fine particles.

Teacher's Note

When you write with chalk on the board, small particles stick to the board. This is like how dust particles stick to a cloth when you wipe the table at home.

Exam Trick

Remember: All things are made of tiny particles. Think of sugar - when you crush it, it becomes powder made of many small pieces.

Points to Remember

All substances are made of very tiny particles.
When you break or pound something, you can see the particles.
Chalk particles stick to the board when you write.
Coal, sugar, and other solids can be broken into fine particles.
Even liquids and gases are made of tiny particles.

Can You Tell?

If there is a sudden shower, we take shelter under a roof at the roadside. Even though the rain does not fall on us directly, we get wet to some extent. Why?

The raindrops that fall on the road, bounce off and break up into droplets. These droplets are also made up of tinier particles of water. They make us wet. It means that liquids are also made of small particles.

Use Your Brain Power!

Make a list of all the everyday substances that we use in the form of a powder.

Naphthalene balls are placed in warm clothes. After some days, why do the clothes also smell of naphthalene?

Naphthalene balls are also placed in toilets. Why do they become smaller after a few days?

Naphthalene is continuously being converted into small particles in the gaseous state. Such small particles from the balls settle on the clothes. So, the clothes too smell of naphthalene. As the particles leave the naphthalene balls, the balls grow smaller in size and slowly disappear.

Particles of rangoli are fine like a flour. Rangoli colours are also available in the form of grains.

Use Your Brain Power!

Suppose you do not have rangoli powder. What things can you use as an alternative?

Teacher's Note

Naphthalene balls are used in our cupboards to keep clothes safe from insects. The smell comes from tiny particles that leave the balls and spread in the air.

Exam Trick

Remember: Naphthalene balls become smaller because particles escape as gas. Think of how your favorite perfume bottle becomes empty - the liquid changes to gas particles in the air.

Points to Remember

Naphthalene balls release tiny particles into the air.
These particles can be seen as a smell in clothes.
Liquids are also made of tiny particles.
Rain bounces and makes smaller droplets.
Powders are substances broken into very fine particles.

Do You Know?

The theory that all substances are made of minute particles was proposed long ago by Kanaad Maharshi. Kanaad Maharshi was born in the 6th century BC at Prabhaas Kshetra near Sorati Somnaath in Gujarat. His given name was Uluk. He proposed that all things in the world can be classified into seven categories. He was also the first to suggest that every object in the universe is made up of minute particles. He named that tiny particle, 'peelav'.

Use Your Brain Power!

The small particles of various substances that we can see are themselves made up of many tinier particles. These tiny particles are so small that they are not visible to our eyes. Lakhs of particles of any substance must come together to form a particle that can be visible to us.

Use Your Brain Power!

What are the small particles that can be seen in a beam of light that enters a dark room?

Teacher's Note

Kanaad Maharshi was an ancient Indian scientist who discovered that all things are made of tiny particles. He lived more than 2000 years ago, just like how scientists today study atoms and molecules.

Exam Trick

Remember: Kanaad Maharshi = Ancient Indian scientist. He said everything is made of tiny parts. Think of LEGO - many small blocks make one big toy.

Points to Remember

Kanaad Maharshi was born in Gujarat in the 6th century BC.
He said all things are made of tiny particles called 'peelav'.
He divided all things into seven types.
His idea about particles is still used in science today.
This is a very old Indian discovery about matter.

Substances and Objects

The States of Substances

Water is found in nature in three states - solid, liquid and gaseous. In all the three states, the individual particles of water remain the same. However, the arrangement of the particles in each of these states is different.

As a result, we see differences in the properties of solids, liquids and gases. All substances in nature have a particulate form, i.e., they are made up of particles. In nature, every substance occurs in a specific state. Accordingly, that substance is called a solid, liquid or gas. For example, aluminium and coal are solids, kerosene and petrol are liquids while nitrogen and oxygen are gases.

Different substances have different properties. Substances may differ with respect to properties like hardness, transparency, colour, smell, solubility in water, etc.

Can You Tell?

Look at the objects in the picture above. What substance are they all made from?

Asmita went to buy an earthen pot. There she saw many things kept for sale. How did she identify what she needed? From what substance had the potter made all the things?

What is the difference between a substance and an object?

Objects have a definite shape. Their parts are put together in a particular way. Objects are made from substances.

Teacher's Note

Ice, water, and steam are all the same substance - water. But they look different because their particles are arranged differently. Like how a potter makes pots and cups from clay.

Exam Trick

Remember: Substance = material (like clay). Object = thing made from it (like pot). Same clay can make different pots.

Points to Remember

Water has three states - solid ice, liquid water, and gas steam.
In all three states, the particles are the same.
Only the arrangement of particles changes.
Solids have a fixed shape and size.
Objects are made from substances by changing their shape.

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