Investigating Osmosis Using Potato Cylinders
The aim of this investigation is to see how the sugar concentration of
a solution eventually affects the size of a submerged potato
cylinder. I am conducting this experiment to further my understanding
of osmosis. The increase or decrease of the size of the potato
cylinder can be explained by osmosis.
The core scientific principle, related to my investigation is that of
Osmosis, below I intend to relay information thus.
Osmosis is basically a form of diffusion, but more specifically: it
is the movement of water molecules from an area of high water
concentration, through a partially permeable membrane to an area of
lower water concentration.
Partially permeable membrane:-
A partially permeable membrane is a membrane, with holes so small that
only water molecules are small enough to fit through, bigger molecule,
for instance, sugar and salt are not small enough to fit through.
In my experiment I will be testing Osmosis with a potato in relation
to the solution that it is in, one solution will be pure water, the
second will be a 5% glucose concentration, and then the next a 10%
glucose concentration, and then a 15% glucose concentration. My
hypothesis and the experiment will predominately affected by the type
of solution that the potato cylinders are in, i.e. the solution that
the potato cylinders are in will affect the results, that is whether
the potato cylinders shrink, stay the same size, or grow larger:
Hypertonic Solutions: In a hypertonic solution the solution will have
a higher solute concentration that the potato would, when the potato
is placed inside this kind of solution water will diffuse out of it,
in to the solution causing it to shrivel.
Hypotonic Solutions: In a hypotonic solution the solution will have a
lower solute concentration that the potato (or any plant placed into
it), when the potato is placed into this sort of solution, more water
will flow into it than will flow out causing the plant/potato to
become turgid; with the risk of it exploding.
Isotonic Solutions: In a Isotonic Solution, water concentration, and
solute concentration are equal in the solution and in the plant/
potato. A dynamic equilibrium will exist between the number of water
molecules entering and leaving the cell. The plant in this case will
retain its size.
Hypotheses: I hypothesis that when the potato cylinder is in the
solution of distilled water it will not change size as the distilled
water solution is a Isotonic solution, and as outlined in my