Why does a good solar collector have to move throughout the day? really simple i'm very bad at science.

Excuse me ... you don't get off that easy.

You may have noticed that the sun moves through the sky during the day. 
It rises over on this side (east) in the morning, and sets over on that side
(west) in the evening, and most likely spends the time between morning
and evening drifting slowly across the whole sky.

A solar collector works best, and collects the most solar radiation, when
the sun is shining on it directly ... not on the back of it, not from the side
of it, not slanting down on it, but straight and square.

Since the sun moves across the sky during the day, you must move
your solar collector to follow the sun across the sky, and keep the sun
shining on it straight and square.

This has nothing to do with being good or 'bad at science'.  If you're
watching a possum sniff around under a bush in your yard at night,
I'm sure you know that if the possum moves, you must move your
flashlight to follow it, or else you won't see it in the darkness.  This
does not require any scientific brilliance.  You do it by instinct.