Page 260 - New Medley 4 Semester 2 PDF (Merged)

STEM ACTIVITY 4

Showing that hot air is lighter than cold air
¶ Take a long and thin wooden stick.
¶ Tie a piece of thread in the middle of the stick.
¶ Hang two identical paper bags at each end of the stick.
¶ Hold the stick by the thread and balance the bags.
¶ Place a burning candle below one of the paper bags (taking care that the
bag does not catch fire). What do you observe?
¶ The paper bag above the candle rises because hot air is lighter than the cold
air. This shows that hot air moves upward.

STEM ACTIVITY 5

Making a solution by dissolving sugar in water
¶ Take a glass half filled with water.
¶ Add some sugar into the water.
¶ Stir the water well with a spoon.
¶ Observe – Can you still see the sugar after stirring?
¶ Sugar mixes completely in water to form a solution and cannot be seen separately.

STEM ACTIVITY 6

Showing that small particles (like salt) can fill the empty spaces
between larger objects (like marbles)
¶ Take a glass container and half-fill it with marbles.
¶ Observe – Do you see some empty spaces between the marbles?
¶ Mark the level of marbles on the glass container using a marker.
¶ Now add 3–4 teaspoonfuls of common salt into the container.
¶ Observe – Do you notice any change in the level of marbles?
¶ Small particles can slip into the gaps between bigger objects because
they are tiny and can fit into empty spaces. Salt

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