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Report on Osmosis in potato cylinders
Aim:
To investigate the effect of varying concentration of a saline solution on potato cylinders of a given size, by osmosis.
Hypothesis
Osmosis is the passage of water from a region of high water concentration (low solute) through a semi-permeable membrane to a region of low water concentration (high solute).
If the medium surrounding the cell has higher water concentration than the cell, the cell will gain water by osmosis. ...
If the medium has a lower concentration of water than the cell, the cell will lose water by osmosis. ... 03
Conclusion (of pilot experiment)
It is clear that each potato regardless of size has been affected by the process of osmosis, merely by the fact they all lost weight. ... As surface area is a factor in osmosis, this will be kept constant in the main experiment. ... The pilot test also lead me to realise the extraction of more results would reconfirm my theory of osmosis. ...
If any of the non-variables are not kept constant it would produce an unfair test, for example, if one potato cylinder was 1 cm longer than the others were, the surface area would be larger and there would be more space for osmosis to occur. ... Variables Non-variables
Solution concentration Surface area
Temperature
Solution volume
Weighing scales
conditions
Planned method:
I have altered the main investigation from the pilot test because I have concluded that surface area is a crucial factor in the process of osmosis. ... I am aware that this part of the process must be done as accurately as possible, as a change in the surface area may allow more or less osmosis to occur. ...
Measurements to be obtained:
Pre experiment weight
post experiment weight
Pre experiment length
Post experiment length
Overall appearance both post and pre experiment
Feel of cylinders both pre and post experiment
Predicted out-come:
Test tube 1 submerged in 20ml of 1 molar saline solution should loose H20 through osmosis and therefore be reduced in size and weight. ... The reason for this being the solution has a lower concentration of water than the cell-The cell will lose water by osmosis, more water will leave the potato cells than will enter them, therefore the cell will loose H20 and shrink resulting in weight loss. However, the cylinder in test tube 6 submerged in 20 ml of water should in fact gain weight/size through the process of osmosis. ... The cylinder in test tube 6 however would not fit back into the original corer, further displaying acts of osmosis, and its overall weight gain and the others weight loss. ... The potato cells, depending on which solution they were bathed in, absorbed or released H2O (Osmosis). ...
According to the graph, the extent of osmosis (water lost) was loosely proportional to the concentration of the solution. ... Indicating that there is a limit to osmosis for this particular experiment.
The osmosis might reach this end point because the cells have reached a state of equilibrium, where the concentration within the potato cell is equalled to that of the surrounding solution. ...
Osmosis- in the body
The process of osmosis is used throughout the body in many vital functions examples of these is as follows:
Kidneys
Blood is filtered by the bowmens capsule into the tubule. ...
Maintaining cells
The solute concentration within the cells helps keep water in essential for cell viability
Absorbing water in gut
Absorption of water in the gut is done entirely by osmosis
Oedema (a pathological condition)
Accumulation of fluid in the body tissues.
Approximate Word count = 2940
Approximate Pages = 11.8
(250 words per page double spaced)
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