4. i plan to spear a fish that is swimming in a lake. do i need to understand refraction in order to succeed? why or why not?

Yes, you need to understand refraction, because refraction is when an object bends when going into a different medium, meaning, when you put the spear from air to water, it will bend the shape making it harder to spear the fish.
Hopefully that helps!

You will need to understand refraction, because objects you see from the surface of water, are not really in the same place as you see them. for example, a fish that you see in a pond might be slightly to the left or right underwater.

This is what i found on google “according to the collision theory, the following criteria must be met in order for a chemical reaction to occur: molecules must collide with sufficient energy, known as the activation energy, so that chemical bonds can break. molecules must collide with the proper orientation.” i hope this information you.