Class 9 Science- Chapter 1- Matter In Our Surroundings – Activity 1.1: Demonstrating Particles of Matter Have Space Between Them

Activity 1.1: Demonstrating Particles of Matter Have Space Between Them

Objective

To show that particles of matter have space between them by dissolving sugar or salt in water.

Materials Needed

• A glass or beaker.
• Water.
• Sugar or salt.
• A spoon for stirring.

Steps to Perform the Activity

1. Take a glass of water and mark the initial water level.
2. Add a small amount of sugar or salt to the water.
3. Stir the water until the sugar or salt completely dissolves.
4. Observe the water level after the sugar or salt dissolves.

Observations

• The sugar or salt disappears completely in the water after stirring.
• The water level does not increase after the sugar or salt dissolves.

Concepts Behind the Activity

1. Particles Have Space Between Them
   The sugar or salt particles occupy the spaces present between the water particles. This is why the water level does not rise after the sugar or salt dissolves.
2. Dissolving Process
   When sugar or salt is added to water, its particles break apart and mix with the water particles. This mixing happens because there are tiny spaces between the particles of water that allow the sugar or salt to fit in.
3. Even Distribution
   Once dissolved, the sugar or salt particles spread evenly throughout the water. This is why the water tastes sweet or salty everywhere, not just in one part.

Also Check – Chapter 1 -MATTER IN OUR SURROUNDINGS -Class 9 – Simplified notes

Intext and additional Question Answers on Activity 1.1: Demonstrating Space Between Particles

Question 1: What do you think has happened to the salt?

When salt is added to water, it dissolves, breaking into its smallest particles (ions of sodium and chloride). These tiny particles intermingle with the particles of water, making the salt appear as if it has “disappeared.”

Question 2: Where does it disappear?

The salt particles occupy the spaces between the water particles. Matter, at a microscopic level, contains spaces between its particles. The dissolved salt molecules fit into these spaces, distributing themselves uniformly in the water.

Question 3: Does the level of water change?

No, the water level does not increase. This is because the salt particles settle into the empty spaces between the water particles, maintaining the overall volume of the liquid.

Additional Question: Why do salt and water particles mix without increasing the water level?

Salt particles are much smaller than the spaces between water molecules. This allows the salt to dissolve completely into the water without displacing or adding to the volume. This phenomenon supports the concept that matter is made up of particles with spaces in between.

Key Learnings

1. Space Between Particles
   Matter is not continuous; it has gaps between its particles. This activity proves that the particles of water have space for other particles like sugar or salt to fit in.
2. Particulate Nature of Matter
   The activity highlights that matter is made up of particles, and these particles are not tightly packed. This allows them to interact and mix with other matter.
3. Dissolution
   The process of dissolving sugar or salt demonstrates how substances interact at the particle level.

Conclusion

This activity shows that particles of matter have spaces between them. Sugar or salt dissolves in water without increasing the water level because the sugar or salt particles fit into the spaces between the water particles. This is a simple demonstration of the particulate nature of matter and the existence of spaces between particles.