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Remote Ready Biology Learning Activities has 50 remote-ready activities, which work for either your classroom or remote teaching.
on the change of the onion cells.
Vivian Cruz, Saskia Guerrier, Eurie Kim
Observations
The onion layer on its own...
1) cell membrane
2) full purple coloring (from the purple skin/peel) within the membrane
When 1%NaCl (salt) was added to the onion layer...
1) the purple coloring along the rims of the cell membrane started pulling inwards
2) the more gaps started to form in the inner parts of the cell
3) little, tiny wrinkles formed along the edges of the cell membrane.
When distilled water was added back to the onion layer...
1) the gaps that formed in the inner parts of the cells started to slowly disappear
2) the purple coloring started to fill the cell again, but there is still a slight empty rim along the membrane
Our Story
At first, we thought the onion cells were making room for the salt, but it did not do the same for the distilled water, which means something in the salt is
causing the "shriveling"changes.
So then we think that the salt is drying up the water in the cells causing it to shrivel and create gaps within the cell membranes. These gaps would've been where the water was stored. Therefore, we believe that cells need water.
BUT we also think that the movement of the salt was too slow to move across the membrane, so that's why the cells had gaps along the walls for the salt (the salt was taking up space). On the other hand, the movement of water was fast enough to move across, therefore, refilling the onion to its almost-original state.
So what's the deal with the water molecule?