Class Review 9/19/11

Today in class, we took the last data for our Duckweed experiment. In groups, we have been conducting an experiment on Duckweed. It is to see how quickly the Duckweed reproduce and if other things within the beaker affect the growth. For example, a group put motor oil in the water along with the Duckweed. Another group placed Hornworts in the beaker as well. In some cases, the growth of the Duckweed was affected, and in others, nothing changed.

Another thing we did in class was turn in the homework which was the comparison chart for sections 6.2 and 6.4. We went over the homework that was assigned for this week which is:

• Duckweed Presentations


• read 6.3


• post Muddiest Point to blog


• comment on a post

Finally, we did the Water Testing Lab. We did this to see if the Des Plaines River was polluted. Our class predicted the river would be polluted because of bacteria, and waste from insects and other living organisms found in the water. We tested 8 pollutants to see how comtaminated the water is.

1. Coliform bacteria - pollution from sewage
2. Dissolved Oxygen (DO) - you want a high level of this because it is good for organisms.
3. Biological Oxygen Demand (DOB) - is the amount of DO used by bacteria when they break down waste.
4. Nitrates - if the levels are high, it is from sewage and fertilizers
5. pH - industrial wastes, mining operations, etc. affect this
6. Phosphates - high levels mean it's from human and animal waste and farm run off
7. Temperature - thermal pollution comes from industries
8. Turbidity - is how clear the water is. Can be affected by soil erosion and algae blooms.


For our group, we came to the conclusion that the river water is somewhat polluted.

JESSICA is the next scribe!