Practicals on Changes in Matter – JSS1 Intermediate Science Lesson Note (First Term)

Today, we are moving away from our textbooks and using our hands! We have learned that matter can change physically (temporary) or chemically (permanent).

But how do we prove it? We do this through Experiments.

Safety First!

Before we start, remember:

• Wear your lab coat.
• Do not taste any of the materials.
• Be careful with the matches and burners.

Our Goal: To observe how substances change and decide if a new substance was formed or not.

EXPERIMENT 1 – PHYSICAL CHANGES

Activity A: The Disappearing Sugar

Materials: A glass of water, a spoonful of sugar, and a stirrer.

1. Action: Stir the sugar into the water until you can’t see it anymore.
2. Observation: The water looks clear, but if you taste it (don’t do this in the lab unless told!), it is sweet.
3. The Test: If we boil the water away, the white sugar crystals appear again at the bottom.
4. Conclusion: This is a Physical Change. No new substance was made; the sugar was just “hiding” in the water.

Activity B: Melting Ice

Materials: Ice cubes and a beaker.

1. Action: Place ice cubes in a beaker and leave them on the table.
2. Observation: The solid ice turns into liquid water.
3. The Test: Put the water back in a freezer. It turns back to ice.
4. Conclusion: This is a Physical Change because it is reversible and it is still water.

EXPERIMENT 2 – CHEMICAL CHANGES

Activity C: The Burnt Paper

Materials: A small piece of paper, a metal tray, and matches.

1. Action: Place the paper on the tray and carefully light it with a match.
2. Observation: The white paper turns into black/grey ash. Smoke is released into the air. Heat and light are produced.
3. The Test: Try to turn the ash back into the white paper. Can you do it? No!
4. Conclusion: This is a Chemical Change. A new substance (ash) was formed and it is permanent.

Activity D: The Rusty Nail

Materials: Two iron nails, water, and two jars.

1. Action: Put one nail in a dry jar. Put the second nail in a jar with a little water and leave it for 3 days.
2. Observation: The dry nail is still shiny. The wet nail has a reddish-brown “crust” on it.
3. Conclusion: This is a Chemical Change. The iron reacted with water and air to create a new substance called Rust.

LABORATORY REPORT SHEET

When scientists finish an experiment, they fill out a report. Use the table below to record what you saw today.

Results Table

Final Discussion Questions

1. In which experiment did you see light and feel heat?
2. Why is dissolving salt in water a physical change and not a chemical one?
3. If you fry an egg for breakfast, is that a physical or chemical change? Why?

Homework Assignment

Go home and look at a candle burning.

• The wax melting and dripping down is which type of change?
• The wick (thread) burning away is which type of change?
• Write down your reasons!