This beaker of pond scum sits on a sunny window sill in my lab. It's leftovers from a pondwater microscope lab that we completed before Christmas.
When the sun blasts through the south facing window adjacent to the beaker, the scum revs it's photosynthetic engine and streams of bubbles flow upward.
I keep it there for the kids. It's one thing to hear me drone on about glucose production, balancing the photosynthesis equation, and how the oxygen produced is just a by product. I like to tell the knuckleheads, " Suppose your friend had built a car out of 36 Leggo blocks, then passed the car to you. You disassembled his Leggo car and built a boat out of 24 of those blocks. The boat was perfect and you had no use for the extra 12 leggos. They were simply leftovers."
THAT'S the oxygen produced in photosynthesis."
It's quite another thing to peer into a sunlit Pyrex beaker and see life sustaining oxygen literally pouring from something as simple as some green pond scum.
Now, I need to head to work. My pond scum has been alone all weekend and it misses me.