What is this topic:
Ans: Heat Expansion
Explain how this happens:
In the day, it is hotter, the surrounding temperature is higher. Since metal is a good conductor of heat, the heat will cause the metal tracks to expand. The gaps are constructed to allow for expansion during the day to prevent buckling of the tracks and causing the train to derail.
What is this topic:
Ans: Heat Conductors
Explain how this happens:
For cooking pot, heat is required to be conducted from the flame to the base of the pot fast in order to cook the contents in the pot, thus using material like iron, copper etc which are good conductors of heat is preferred.
As for the handle, since our hands will touch it often and in order not to scald our hands, using material like plastic or wood will be ideal as these materials are bad conductors of heat / insulators and they will conduct heat slower from the pot to the handle and our hand will not be scalded.
What is this topic:
Ans: Heat Travels from Hotter Place to a Colder Place
Explain how this happens:
Iron rod is a good conductor of heat. As the candle is heating the iron rod at one side, the heat will travel along the iron rod from a hotter place to a colder place. Since Thumbtacks P is nearer to the candle, the wax at P will melt first causing Thumbtacks P to drop first.
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