When a substance boils the molecules within the substance move faster and farther apart, meaning (depending on the current matter state of the substance) molecules will go into more liquid and gaseous states
solid----> liquid ----> gas
In the case of something boiling the substance goes from liquid to gas due to the increased molecular activity because to heat...
Answer:
I think they use it at night because they want to avoid involving themselves in road accident while crossing the street. When there are reflective strips on their clothes, drivers do notice them even at far ends of the street since the strips will reflect the rays from the car lights to the driver,hence, the driver notifies that there is a pedestrian crossing and therefore slows down.
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