Page 76 - CT&AI_CLasa_7_Part_1

Heat Transfer in

7 Nature

computational thinking quest

Tick ( ) the correct option.
1. A new building is being fitted with smoke makes things worse because the leaked liquid
detectors. The safety engineer explains that will warm the outer tumbler. The shopkeeper
smoke detectors work by sensing particles says the arrangement does help keep the
suspended in air. Hot smoke from a fire lassi cold.
always rises rapidly towards the ceiling before
spreading sideways. The engineer must
choose between three mounting positions —
near the floor, mid-wall, or ceiling.
Where should the smoke detector be installed,
and what is the scientific principle that makes
this the only correct position?
(Abstract Thinking)

(a) Near the floor, smoke eventually
sinks when it cools. Who is correct, and what role does the air
gap between the two tumblers play in heat
(b) In the middle of the wall, it detects transfer? (Decomposition)
both rising and falling smoke.
(a) The shopkeeper is right, the air gap
acts as an insulating layer, slowing
(c) On the ceiling, hot smoke rises by heat transfer from the warm
convection and reaches the ceiling surroundings into the cold lassi.
first, ensuring earliest detection.
(b) The customer is right, leaked liquid
(d) Anywhere, smoke fills the room conducts heat inward, warming
uniformly within seconds. the lassi faster.

2. A shopkeeper serves cold lassi in a leaky (c) It makes no difference, the
tumbler. He places the leaky tumbler inside a temperature of lassi depends only
second tumbler. The lassi now sits in the inner on the glass material, not air gaps.
tumbler, while a thin air gap exists between (d) The arrangement helps only if the
the two tumblers. A customer argues this outer tumbler is made of metal.

74 Computational Thinking-7 (Science)