Why are clouds White? Why does a day have 24 hours?
Answer: A cloud is a visible accumulation of very tiny water droplets or solid ice that float in the air. Clouds are usually white in appearance due to the fact that it reflects all the visible wavelengths of light from the sun. The sun's light made up of different colors(rainbow colors)that appear as a white light when combined. These colors can demonstrated using a prism that scatters the sun's light. The water droplets or ice crystals that make up the cloud reflect all the light of the seven visible wavelengths (red, orange, yellow, green, blue, indigo, and violet) all together without dispersing each color. Thus the clouds are white because they effectively reflect the wavelengths of visible light spectrum of the sun in all directions more or less equally. Answer for 2nd Question For thousands of yearspeople all over the world have been using terms and divisions like "day","night","hour", "minute", "yesterday", "tomorrow" to talk about lengths of time The idea of "a day"- from when the sun rises to when it sets-has always been a pretty basic way of thinking about time. Within "a day" people usually break down time into units we call hours. Nobody knows the exact reason why it was decided to measure out an hour so that 24 of them would fit in to a day, but we do know the practice goes all the way back o the ancient Egyptians. One reason they choseto divide a day in to a 12-hour day and a 12-hour night is probably because they used to count a system based on 12. Its also possible they chose 12 because that was the number of moon cycles in a year. , The Egyptians made and used sundials to tell time and by looking at the remains of these, we can trace what is believed to be the origins of our 24-hour day back to them.