If you’ve ever owned a fish tank, you know that you need a filter with a pump. Other than cleaning out the fish poop, why else do you need a filter? (Hint: think about a glass of water next to your bed. Does it taste different the next day?)
There are tiny air bubbles trapped inside the water, and you can see this when you boil a pot of water on the stove. The experimental setup shown in the video illustrates how a completely sealed tube of water can be heated… and then bubbles come out one end BEFORE the water reaches a boiling point. The tiny bubbles smoosh together to form a larger bubble, showing you that air is dissolved in the water.
Materials:
- test tube clamp
- test tube
- lighter (with adult help)
- alcohol burner or votive candle
- right-angle glass tube inserted into a single-hole stopper
- regular tap water
When water sits in a fish tank without circulation, then there is nothing to replace the oxygen the fish breath out of the water. Also, the warmer the water is, the more air will escape out of the water. Yes, less air will escape when in a cold climate, but there still needs to be circulation to introduce new oxygen into the water. As you said tides, wind, storms, and currents help distribute oxygen. Lakes and ponds often have rivers or small creeks that introduce turbulence…which introduces air. But, fish are less likely to survive in a pond that is stagnant. Keep in mind that underwater plants help introduce oxygen, but there still needs to be movement in the water to distribute that oxygen.
This experiment demonstrates that air is dissolved in water and that the amount of air dissolved varies based on the water’s temperature. If a body of water is stagnant and gets too warm, there may not be enough air for the fish to breath.
I’d like to re-ask this question. Is heating up the water and the air escaping in the test tube similar to air sitting still in a fish tank and the air leaving? What if water sat still in a very cold climate? Would less O escape? Does it then escape faster in warmer climates? And does this mean that while the ocean is constantly moving (tides, wind, storms, etc.) that this helps to keep the O adding? How about lakes, ponds, puddles? thanks
I still don’t understand how the connection of this experiment to fish needing the air.