Mixing Materials

• Define a mixture as two or more materials put together.
• Identify mixtures that blend well and those that separate again.
• Observe that mixing does not always create a new substance.
• Connect mixing to everyday kitchen and classroom activities.

Level 1 - Meaning of mixing

When two or more materials are put together without a chemical change, we get a mixture. Each material in the mixture keeps its own properties.

Level 2 - Types of mixing

Some materials mix evenly, like salt stirred into water. Some materials do not mix and settle apart, like oil poured into water. Some solids mix but stay as separate visible bits, like rice mixed with pulses.

Level 3 - Everyday observations

Mixing sand and water gives a cloudy mixture that settles when left still. Mixing two colours of paint gives a new shade, but the colours can still be told apart under a microscope. Mixing pulses of different colours for rangoli keeps each grain unchanged.

Level 4 - Indian context

Chaat and chutney are made by mixing many ingredients like tamarind, spices, and vegetables, yet each ingredient can still be tasted separately. Farmers mix different seed varieties in a sack for storage, and the seeds can be picked apart later. Mixing colours during Holi shows solids blending temporarily with water.

NCERT anchor: Looking Around 4, Ch 10 — Take Care of Your Teeth (background chemistry link), Ch 6 — Making a Difference (materials in daily life)

Sand and water mixture

Step 1 - Add a spoon of sand to a glass of water.
Step 2 - Stir well and watch closely.
Step 3 - Let the glass stand for two minutes.
Step 4 - Sand settles at the bottom; water stays on top.
Answer: Sand and water form a mixture that can settle apart.

Oil and water mixture

Step 1 - Pour a spoon of cooking oil into a glass of water.
Step 2 - Stir the mixture briskly.
Step 3 - Leave the glass undisturbed for a minute.
Step 4 - Oil floats back up as a separate layer above water.
Answer: Oil and water do not mix permanently; they form two layers.

• What is a mixture?
• Does sand mixed with water separate on standing?
• Why does oil float above water after stirring?
• Give one Indian food example that is a mixture of many ingredients.
• Stretch: Mix rice and pulses together, then think of one way to separate them again without water.

Revision tip: In a simple mixture, each material keeps its own properties and can often be told apart again.

Open the Practice tab for graded questions on Mixing.