Question

two identical aquariums were next to an open window. one aquarium had a plastic cover on it, and the other was uncovered. this table shows how the temperature of each aquarium changed over 1.5 hours.

aquarium	initial temperature (°c)	final temperature (°c)
covered aquarium	21.6	17.0

during this time, thermal energy was transferred from __ to __
the surroundings... each aquarium
each aquarium... the surroundings

Explanation:

Step1: Analyze temperature change

The initial temperature of both aquariums is 21.6°C and the final temperature is 17.0°C. The temperature of the aquariums decreased.

Step2: Determine heat - transfer direction

Heat transfer occurs from a region of higher temperature to a region of lower temperature. Since the temperature of the aquariums decreased, thermal energy was transferred from each aquarium to the surroundings.

Answer:

each aquarium... the surroundings