Saturday, 23 August 2014

question 5: why did the two colors eventually mix?
ans: even though convection did not occur, the water still gained and lost thermal energy to the surroundings and each other, and when they reached the same temperature, they mixed together.
question 5: explain the phenomena. an ice cube with a wire sinks to the bottom of a teat tube. the top is heated. ice does not melt.
ans: water is a bad conductor of thermal energy, and as the heating occurs at the top, where the lighter, less dense, warmer water is, convection does not occur, making the transfer of thermal energy very slow.
question 4: wht did the green water sink to the bottom?
Ans: it was colder than the warmer red water, making it more dense, causing it to sink beneath it.
question 3: What should be done to let the ball pass through the ring?
ans: it should be heated. every atom in the loop is moving and equal distace,relative to the temperature change,away from other adjacent atoms. Thus, both the outer and inner diameter increases along with the width of the material.
first question: why do we feel cold when we step into and air conditioned room?

Ans: because when we step into an air conditioned room, the temperature of the surroundings is much lower that the temperature our body is used to, and so we feel cold.

Question 2: why do we shiver when we go out of the pool on a hot day?
Ans: when the water droplets on our exposed skin change state, they use a lot of energy to make the change of matter, as a lot of energy is required to break the bonds of attraction between the water molecules.Thus, when we get out of the pool, the water uses our body heat to change state, and as heat leaves our body rapidly and suddenly, the muscles in the body shiver to generate more thermal energy.