How frequently should one apply sunscreen while swimming on a sunny day? once since water absorbs uv rays more often since water reflects uv rays once since water reflects sun's radiation more often since water absorbs sun's radiation this is science

More often since water reflects UV rays  

Explanation:

Dermatologists are unanimous in stating that, like most mosquito repellents, sunscreen should be applied half an hour before sun exposure and reapplied every two hours. This interval is best suited for the skin not to be unprotected at any time.

Also, sunscreen should be reapplied whenever the person gets sweaty or gets into the water. Contrary to popular belief, water reflects only 5% of sunlight.

For this reason, we can say that sunscreen should be applied more often because water absorbs radiation from the sun.

well when looking at this if you think about it   negativley and positivley   react with each other and when the first layer gets full they add layers it starts with 2 on the first layer and it constantly goes on until the official number is there

if u need the answers look it up on google youll find it trust im just saying this incase no one out : )