Question

student sets up an experiment by placing a jar of cold water colored yellow over a jar of hot water colored blue. After a few minutes, the water turns green as the water in the two jars mixes.



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Which is the BEST explanation for this observation?



A.
The yellow water has less energy and is more dense so it moves downward. The blue water has more energy and is less dense so it moves upward. The water mixes due to conduction.

B.
The yellow water has less energy and is more dense so it moves downward. The blue water has more energy and is less dense so it moves upward. The water mixes due to convection.

C.
The yellow water has more energy and is less dense so it moves downward. The blue water has less energy and is more dense so it moves upward. The water mixes due to conduction.

D.
The yellow water has less energy and is less dense so it moves downward. The blue water has more energy and is more dense so it moves upward. The water mixes due to convection.

Answer 1

B

Cold (yellow) water has less thermal energy and is denser, so it sinks; hot (blue) water is warmer and less dense, so it rises. The bulk movement and mixing is caused by convection.