Temporary changes would be weather, since it can change at any givin time another example would be tides coming in because they vary by day, or wet sand becoming dry sand!
Volume the volume of the test tube is approximately 35cm so the water is 20m/cw idk if this helps
UV rays reacting with the O2 molecules
I might be wrong a little but
Hope the helps :)
In the south it becomes 24 hour darkness and in the north it is 24 hour sunlight
