Wednesday, February 25, 2009

Lake Core Investigation

Hello, our names are Ally, Dana, Courtney, and Derek, we are in earth science and we are studying lake cores about diatoms.

Question: How many diatoms are there at 60cm compared to 10cm?

Variable Measured- How many diatoms.
Variable Changed- The sample at 60cm compared to 10cm.
1. Get the cores out and materials ready.
2. Get sample at 60cm, and put on a slide
3. Look at the sample under the microscope and count the diatoms.
4. Wash the one sample off.
5. Get sample at 10cm and put it on a slide.
6. Count the diatoms and record data.
7. Wash that slide off and do all the data.
8. Repeat the steps at each spot 4 times and count the diatoms from each one and record data.

- 8 slides
- Core sample (at 60cm and 10cm)
-8 slide covers
-8 tooth picks
-Water dropper

Sample 1- At 10cm we found 3 diatoms, and at 60cm we found 2 diatoms
Sample 2- At 10cm we found 4 diatoms, and at 60cm we found 5 diatoms
Sample 3- At 10cm we found 2 diatoms, and at 60cm we found 2 diatoms
Sample 4- At 10cm we found 5 diatoms, and at 60cm we found 2 diatoms
Total- At 10cm there were 14 diatoms total and at 60cm we found 11 diatoms total!


Claim- we found that there are more diatoms at 10 cm then at 60 cm. there were 14 diatoms at at 10 cm an 11 diatoms at 60 cm.

Evidence- We took 4 samples at both 10 and 60 cm. The first sample at 10 cm had 3 diatoms the 2nd one had 4 diatoms, the 3rd one had 2 diatoms and the 4th one had 5 diatoms. totaling 14 diatoms. Our 4 samples at 60 cm at 2 diatoms on the first slide, 5 diatoms on the 2nd one, 2 diatoms on the 3rd one and 2 diatoms on the 4th one, all totaling 11 diatoms.

Reasoning- This may be becuase at 60cm it was older because it was closer to the bottom, so there would be older and less diatoms then there would be at 10 cm, because the soil at 10 cm is newer and closer to the top.

Further Questions-
1. Would the amount of diatoms differ if we took samples at 20 and 70 rather then 10 and 60 cm?
2. If we used 2 different core samples and took samples at 10 cm and 60 cm would the amount of diatomns differ between the two cores?

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