First:why sky's blue???? because

A clear cloudless day-time sky is blue because molecules in the air scatter blue light from the sun more than they scatter red light. When we look towards the sun at sunset, we see red and orange colours because the blue light has been scattered
out and away from the line of sight


Why snow is white???: because
Every drop of water reflects all colors ,thus the milangs is white.

Why if u stare at something then close ur eyes u'll still see somehow the image??: because
everything we see persist in our vision till0.1 sec

Why do they advise those suffering from osteoporosis to have exercise?? because
when we have exercise we bend our bones joint which will create an electric circuit of positive n negative charges wich will attract each other


Why fast trains move with that speed without effect of friction?? because
actually fast train they do not move on the track but they just fly above it due to the repulsion of charges on hte track and its bottom.
why would ants climb the wall without falling down?? becz
the wall isnt plain as it seems ,its bumpy and the ant just climbs over the bumps




Hope U R Interested
if one has more do not hesitate to add

with best luck