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These are our observations with an objective of 40x

2 Microns
1st time: 30 micrometers
2nd time: 20 micrometers

Here there was a lot of movement and it was difficult to measure and we kept trying to average it out.


4 microns
1st time: 3 micrometers
2nd time: micrometer

Here, we barely saw any movement and it was hard to tell if they were actually moving or if we just assumed they were.

8 microns
1st time: <1
2nd time: 0

Here we were unsure if there was any movement at all. We ended up wondering whether it was moving but it was too difficult for us to actually see the movement because it was so slight.


Onion Peel Observations

1% salt water:

There was no movement. There were cells that were almost rectangular, like long boxy blobs. Inside of them there were tiny dots. We didn't see anything that was moving inside the cells and the cells themselves weren't moving.

25% salt water:
Now we see the cells but instead of dots inside of them, there is something bigger in the middle of them. We are seeing more than just the cell wall. This is apparently the cell membrane, which has now pulled away from the cell wall and is now more apparent.

Distilled water

With the distilled water the cell is no longer shrinking but is instead expanding.

Conclusion:

Overall we hypothesize that the size of the particle AND the density of the water play a role in the movement of the particles. For example, the first half of the lab we observed that the bigger beads moved much less than the smaller beads in distilled water. This is because the distilled water (being less dense) was randomly moving however, it was not strong enough to move the beads that were much more denser.

In the second half of the lab, we observed that in 1% salt water, the cell membrane of the onion seemed as if it were attached to cell wall (to the human eye). However, when the water was made more dense after an increase in the amount of salt to 25%, the water was able to detach the cell membrane from its cell wall and move it (albeit a small movement) towards the center of the cell. When the onion was tested in distilled water, the cell membrane reverted to being attached to the cell wall again. This is because the water being less dense was not a strong enough force to pus the cell membrane away from the cell wall, therefore the cell membrane remained attached to the cell wall.