1. Light and Life (6/8)
CDOM experiment
Although CDOM is an organic breakdown product that we usually see in nature as humic acids (leeched from soils), the substance that leaches from tea bags placed in water is also an example of CDOM. Two clear coffee mugs and two tea bags (1 Black Tea, 1 Herbal (e.g. Chamomile were used in this experiment. Safety: We provide photo's. Should you however want to repeat this experiment always take care of your safety. You do NOT need to boil the water.
Procedure:
- Half of each clear mug was filled with warm tap water.
- Each teabag was put in separate mug of water.
- Watch for the colour changes in the water and record findings for each of the teas.
- Water was added slowly in into each of the mugs and stirred after each water addition until each mug is full.
- Look at the colour changes when each mug is full
Questions:
Q 1. Why did we use different types of teas (black, herbal)?
Q 2. When you added the teabags to the warm water, what did the substance coming from the teabags represent?
Q 3. What happened when you added more and more water to the mugs?
Q 4. What processes in nature does the addition of water to the mugs represent?
We can also derive CDOM from remote sensing because CDOM is yellow to brownish: CDOM absorbs light in the blue part of the spectrum.
Source: ESA(data) and IVM(inversion)
Extension Questions:
Q 1. What other natural earth materials could we use to demonstrate the same processes as seen with the teabags?
Q 2. What effects does sunlight have on CDOM and DOC?
