Lauren Bracchi
Lauren Elvig
Kevin Mackin
Aaron Boyd
Problem
 How do various factors affect the osmosis of water in
an apple core?
 Our specific problem was how does the change in
concentration of the solution affect the osmosis of
water in an apple core.
Background Information
 Osmosis is a type of passive transport of molecules
through a membrane, it is the diffusion of water
through this membrane. To put it in more specific
terms, it is the movement of water from a lower
concentration of the solute to a higher concentration
of the solute.
Hypothesis
 If we increase the concentration of the solute,
dextrose, then the solution will become hypertonic
and the apple core will lose weight.
Procedure
 Come up with different concentrations for the solution, in our
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case different amounts of dextrose (distilled water, 2%, 4%, 6%).
Obtain 4 apple cores of the same size and take an initial mass.
Record.
Make the first solution by simply measuring 100 mL of distilled
water in a graduated cylinder and then putting it in a cup.
Make the next solution by measuring out 50 mL of distilled
water in a graduated cylinder and adding 2 grams of dextrose.
Mix and stir until dissolved, then add more distilled water until
the solution reaches 100 mL. Put it in a cup
Repeat this step for the other concentrations, using 4 grams of
dextrose for 4%, and 6 grams of dextrose for 6%.
 Put the apple cores in their respective cups, (make sure
you know which mass goes with which apple core), and
wait for 30 minutes to let the osmosis occur.
 When the 30 minutes is done, take out the apple cores
and pat them dry to get all the extra water droplets off the
outside. Then take the final mass of the apple cores.
 Find the molarity of the different solutions by taking the
mass of the solution that we put in the distilled water and
dividing it by the molar mass, then divide it by the
amount of solution (.1 L)
 Also find the % mass change, which is the final mass-the
initial mass and divided by the final mass.
Data
Distilled
Water
2% dextrose
4% dextrose
6% dextrose
Initial Mass
4.61 g
4.48 g
3.4 g
4.75 g
Final Mass
4.8 g
4.5 g
3.4 g
4.6 g
Molarity
0
.111 M
.222 M
.333 M
% Mass
Change
.039%
.0044%
0%
.032%
0.25
Apple Core Mass Change
0.2
Change in mass (g)
0.15
0.1
0.05
Series1
0
0
0.05
0.1
0.15
0.2
-0.05
-0.1
-0.15
-0.2
Molarity (M)
0.25
0.3
0.35
 For the distilled water everything went according to plan
and the apple core gained weight because there was more
sugar in the apple core, so the water diffused into the core.
 For the concentration of 2%, the mass of the apple core
increased as well, however it did not increase as much as in
the distilled water.
 In the cup of 4% concentration of dextrose, we observed
that there was no noticeable change in mass, which means
that it reached an isotonic state.
 In the cup of 6% we found that the mass of the apple core
decreased in mass, because the outside solution was
hypertonic and the apple was hypotonic, so osmosis
occurred out of the core.
Conclusion
 The purpose of this lab was to find out how different factors affect the
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osmosis of water, and in our specific case it was how the concentration
of the solution affects the osmosis.
In our lab we found that for the distilled water the mass increased from
4.61 g to 4.8 g because the apple was hypertonic and the outside
solution was hypotonic, so the water diffused into the apple
We found that for the 2% solution the apple also gained mass, from
4.48 g to 4.5 g, though not as much as the distilled water, but for the
same reasons
For the 4% solution, there was no visible change in the mass of 3.4 g
because the solution had reached an isotonic state.
And finally for the 6% solution, the apple lost mass, from 4.75 g to 4.6 g
because there was more dextrose in the outside solution (hypertonic),
and less dextrose in the apple (hypotonic), so the water diffused out.
 Our data agrees with our hypothesis
because we predicted that as the
concentration of the solution
increased, then the outside solution
would become hypertonic, and water
would diffuse out of the apple core, and
so the core would lose mass. Our data
proves this because as the
concentration went up, the mass of the
apple went down.
An error that could have occurred is
when the apple cores were put in at
different times, which would have
caused inaccurate data if not timed.
Another error that could have
occurred is the solutions could have
been contaminated, and this would
also cause inaccurate data.
 If we were to change anything we would have
made all of the apple cores the same size. The
reason for this is it affects the apple cores
differently if they are different sizes due to
more mass and surface area.
 Another thing we would have done differently
is we would have put the apple cores in at the
same time. We put them in at different times
not keeping track of the time. So we
guesstimated instead of timing. Which caused
us to have inaccurate data.
 We learned about Osmosis in this lab. This
relates to what we are doing because we are, in
fact, learning about osmosis in class. We found
out that and apple is 4% concentration
dextrose. We found this out when we put the
apple core in the 4% dextrose solution and the
apple didn’t change weight after 30 minutes of
sitting in it. It reached an isotonic state. After
the 4% was the 6%, and that apple core lost
weight which means that the concentration
outside of the apple core was greater then the
apple core.