On our Biolgy class we had been seeingthe process of Osmosis, and to finish we went to the lab and made an experiment to see how it was that Osmosis worked. Juan Cruz and I were asked to complete these exercises on the experiment we did in class.
- Cut 4 puedes of potato 4cm long, 0,5 wide, 0,2 high. Se were given half piece of potato and we had to cut into four pieces of specific measures.
- Place 2 pieces in the Petri dish labelled CS. Potato strips had to placed into the Petri dish with a concentrated solución.
- Cover the pieces with the solution CS. We had to pour the solution on the Petri dish and cover the potato strips.
- Place 2 pieces in the Petri dish labelled DW. We had to place the twovother remaining strips in the Petri dish.
- Cover with the solution DW. We had to pour the solution on the Petri dish and completly cover the potato strips.
- Wait for 20-30 minutes.
- Remove pieces from the Petri dish CS and DW. The potato strips had to be taken out of the Petri dish containing the different solutions.
- Record the results in the table:
Osmosis is the process where water molecules move from a region of higher water potential (diluted solution) to a region of lower water potential (concentrated solution), through a partially permeable membrane. We see this present in the experiment. The potato strips that were covered with the CS solution were in a concentrated solution, and this causes for osmosis to take place, water from the potato strip diffues through the partially permeable membrane to create a balance between high and loswater potentials. Causing the strip to shrink and become softer and flaccid. But on the other hand the potate strip on the Petri with the CW solution was on a diluted solution, and this causes for water to diffuse from the outside to the inside, this way the strip absorbed more water and become bigger and more stiff.
When osmosis takes place in animal cells, those in a hypertonic solution (with more solute, concentrated) release water and shrink. And those in a hypotonic solution (less solute, more concentration in the cell) absorb lots of water and burst. We also see this in plants, but unlike the animal cells, plant cells don’t burst because of the prescense of cell walls, which protect and give shape to the cell.
In the following pictures we show the materiales, and different steps of the experiment.