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After finishing the first part of the lab, we proceeded to observe cell movements and how they diffeer when water and/or salt is added.

when we added 1 percent salt walter, the self membrane began to shrink and the gap between the cell membrane and the cell wall began to widen.

However, as soon as we added distilled water, the cell membrane began to expand again, filling up the gap between cell membrane and the water.

we think the shrinkage is due to the simple idea of osmosis. Osmosis is simply water diffusing from a highly concentrated area to a less concentrated area. (remember.. cell membranes are penetrable) this is why adding salt caused the cell membrane to shrink because it caused the water inside the cell to move out. (there is a high concentration of salt outside the onion cell and because of osmosis, water would flow out of the cell in attempt to balance the level of concentration)

Therfore, the cell becomes dehydrated and that is why a gap appears between the cell membrane and the cell wall and is again why this is reversed when we add distilled water.