You pick up a metal spoon and a wooden chopstick that have both been resting for…
PHYSICS · Multi-part · CBSE · Physics · Thermal Properties of Matter · Thermal Properties of Matter
Problem
You pick up a metal spoon and a wooden chopstick that have both been resting for several hours on the same kitchen countertop, which a thermometer shows to be 22 °C. The spoon immediately feels noticeably colder to the touch than the chopstick even though both objects are at the countertop’s temperature.
Answer the following questions about this common observation.
(a) Describe the macroscopic evidence that suggests your fingers are losing thermal energy more rapidly to the spoon than to the chopstick.
(b) Explain, at the particulate level, why energy leaves your fingers more quickly when they contact the spoon than when they contact the chopstick. In your explanation, refer to both (i) the nature of molecular collisions at the interface and (ii) the physical property that differs most between the two solids.
(c) Draw and fully annotate a particle-level diagram (no artistic detail required) illustrating the first few milliseconds after your finger contacts the metal spoon. Your diagram should include the relative speeds of particles in your skin and in the spoon and indicate the direction of net energy transfer.
(d) A friend says, “The spoon is colder because it conducts heat.” Identify and correct the misconception in this statement.