The basic concept for using sunscreens is often misunderstood.
Sunscreens are not intended to prolong the amount of time that children can safely remain in the sun, though this is often what occurs.
Sunscreens are meant to protect skin when exposure is important. For instance, for playground activities and place and time of day should be chosen to minimise exposure to the sun.
Sunscreens usually contain zinc as the active ingredient, they coat the skin to prevent tanning and can be applied just before exposure to sun.