Tuesday, February 24, 2009

Lake Core Investigation

Hello, our names are Nick, Dylan, Eric, and RC. We are doing an investigation on Lake Core Sediments.This is our investigation!

Question: Does the size of a sediment change wirh the core depth of 70cm to 90cm?

Slide Cover Piece
Copound Microscope
Lake Core Samples

1.Gather up all of our materials or supplies
2.Put a tiny bit of the lake sample on slide from 70cm
3.Put 1 drop of water on slide
4.Put slide cover piece over sample
5.Put slide under compound microscope
6.Find sediment size
7.Repeat steps 2-6 but take sample from 90cm
8.Compare sizes of sediment
9.Write down what we see

Variables Changed:We tooks samples from 70cm and 90cm

Variables Measured: Sediment Sizes


We use the same materials

We did the same procedure

Same core sample

And how much we sampled


At 70cm we found out:

Slide 1: smallish shape, long, ovalis, clear, dark specks scattered

Slide 2: slightly bigger, more ovalish, alot of dark specks, less clear, clear spotlight

Slide 3: bigger then slides 1 and 2, less roundish, clear on 1 side, lot of specks, lines coming off of it

Slide 4: same size as #2, very ovalish, lots of specks, clear in center, 1 corner missing

At 90cm we found out:

Slide 1: very large, clear stripes, lots of dark specks, a pointed bottom, flat top

Slide 2: 1/2 size as 1st, egg shape, less clear, lots of specks, 2 bigger specks, another sediments close to it.

Slide 3: slightly smaller than 1st, clear spots on edge, lots of dark specks, design looks like finger print, green lines on it, turtle shape

Slide 4: Same size as 2nd, it has a turdish shape, has a point on the top and the bottom was round, 1 large darks spot, lots of sediments surronding it


We found out that at 90cm there are larger and less clear. Another thing is that in the 70cm mark almost all of the sediments were ovalish and at the 90cm they were a lot bigger and more of a wierd shape, such as eggish, coneish, and one even looked like a dog turd!!! we know it was dryer at 90 than at 70 because the sediments were larger at 90 than at 70. We know this because when it is dryer the sediments stick together than get blown into the lake. But when it is wet out and constantly raining the sediments stay apart from each other and get drained into the lakes when they are smaller.

2 Further Questions:

1. Are ther different types of diatoms at different depths?

2. Does the climate effect how long a diatom lives? If so how?

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