Take two clear glasses of water. Add a spoonful of sugar in one and a spoonful of cooking oil in the other. Stir both well and observe. What do you observe? Which one appears clear?
When sugar is added to water and stirred, it dissolves completely and the water remains clear. The sugar particles mix with water particles and become invisible.
When cooking oil is added to water and stirred, it does not dissolve. The oil forms small droplets or a separate layer on top of the water, making the mixture appear cloudy or unclear.
The glass with sugar water appears clear, while the glass with oil and water does not appear clear.
Explanation
Activity 3 in the chapter demonstrates that some substances dissolve in water while others do not. Sugar is a soluble substance that dissolves completely in water, forming a clear solution. Oil is insoluble in water and forms a separate layer or droplets because oil and water do not mix. This activity helps students understand that harmful substances like chemicals can hide in water even when it appears clean.
Solution Steps
Sugar dissolves completely in water, making the solution clear
Cooking oil does not dissolve in water and forms droplets or a separate layer
The sugar water mixture appears clear, while the oil and water mixture appears cloudy