NAME THE METHOD
A child removes visible stones from a bowl of rice using only their fingers.
What method is being applied here?
Hand picking
Visible, solid impurities are removed manually.
Which tool would you choose if the solid particles are larger than flour grains?
Sieve — it separates solids based on particle size.
Two substances differ mainly in size and are both solids. Which separation principle should be used?
Sieving — separation is based on particle size.
Why is cloth often used while cleaning muddy water in villages?
Cloth acts as a filter, removing insoluble impurities.
Why is handpicking not suitable for separating very small impurities?
Very small particles cannot be easily seen or picked by hand.
A muddy water sample becomes clear after passing through cloth.
Which separation process has taken place?
Filtration
Cloth acts as a filter allowing water to pass while retaining mud.
You want to separate tea leaves from tea without spilling the liquid. What equipment would help you most?
Strainer / filter — it retains tea leaves while letting liquid pass.
One component of a mixture dissolves in water while the other does not. What method would help separate them?
Filtration — it separates insoluble solids from liquids.
During cooking, why is flour sieved before making batter?
To remove lumps and unwanted particles, making the batter smooth.
How does the property of solubility help in separating mixtures?
Soluble substances dissolve in water while insoluble ones do not, allowing separation.
A liquid disappears after heating, leaving behind white crystals.
Which method explains this change?
Evaporation
Liquid changes into vapour, leaving solid residue behind.
A student heats a salt solution in a shallow container instead of a deep one. Why is this choice suitable for separation?
Shallow containers increase the rate of evaporation by providing a larger surface area.
A mixture needs two steps to separate all its components. Why can one method alone be insufficient?
Because different components have different physical properties, so more than one method is required.
Why is winnowing done in open spaces and not inside closed rooms?
Air movement is required to separate lighter husk from heavier grains.
Compare filtration and sieving. Why can one work with liquids while the other cannot?
Filtration separates solids from liquids, while sieving separates solids of different sizes only.
Lighter particles are blown away while heavier grains fall straight down.
Identify the method involved.
Winnowing
Difference in weight allows lighter particles to be carried by air.
A mixture contains iron filings, sand, and stones. Which single tool would help you start the separation process most effectively?
Magnet — it quickly separates iron filings from the mixture.
A student uses evaporation first instead of filtration and fails to separate a mixture properly. What mistake might the student have made?
Insoluble solids were not removed first; filtration should be done before evaporation.
Salt pans are shallow and wide rather than deep. How does this design help in the separation process?
It increases the rate of evaporation, helping salt form faster.
You are given a mixture of sand, salt, iron filings, and water. Explain the correct sequence of methods to separate them.
Magnetic separation – remove iron filings
Filtration – separate sand from water
Evaporation – obtain salt from salt water