The effect of changing the concentration of a salt solution on the movement of water in or out of potato chips.

Apparatus used was

For this experiment we will require:

Test tubes x5

Test tube rack

Beaker

Measuring cylinder

Molar solution

Water

Scalpel

Cutting tile

potato

Weighing scale

Things that I kept the same during the Experiment.

we timed the chips while they where in the solution

the mass of the potatoes at the beginning

All of these things must be kept the same to make this a fair and accurate test. If any of these were changed then the test would be inaccurate and would prove nothing.

Things to change

the volume of water used in each test tube.

The volume of molar used in each test tube.

Method

We take a potato and cut cylinders from it with the cork borer. We then cut disks of potato which all must way 1.0 grams. Then place sticky labels on the 5 test tubes ranging from 0.0 molar to 1.0 molar each one rising .2m each time. Then add water to the solution to make it at10 millimetres. Add two disks to each test tube. Then place the test tubes in a safe place for 24 hours.

We then come back the next day and collect the test tubes, take out each disk dry them and way them. Record the results and clear apparatus away. We can now make calculations with the results.

Evaluation

Although the results of the experiment support my hypothesis there are one or two abnormal results. These could be improved by altering the experiment for example keeping the temperature of the test tubes the same, by storing them in some sort of container or cool box. We could of also measured the exact weight of the potato chip more accurately by using a more precise weighing scale (more advanced). The test also may be more accurate if we allowed the potatoes to rest in the solution for 48 hours in stead of 24 this would give the solution time to penetrate the core of the potato. This would also enable me to find the saturation point (where the potato can no longer take in any more water) and the dehydration point (where the potato cannot lose any more water) and therefore get a more accurate result.

We could have also performed more preliminary tests to decrease the chance of error in the final experiment.

A disadvantage of our experiment is that one anomalous result caused the last results to change slightly. From the beginning the results steadily changing in a constant pattern but after the one odd result the last two results were slightly effected and also dropped down a lot this could of made this an unreliable experiment.

We could have also affected the success of the experiment by comparing our results with other people in the class who used the same measurement as us. This way we can tell if they are accurate or not. One last thing we could of changed is dying the potatoes with the tissue by doing this we could have been extracting some of the liquid from he potato. It would be hard to come up with an alternative for this; if we had the time we could of let them dry in the air.

Although the investigation and experiment could have been improved, the results were accurate enough to support my hypothesis. All the work we have done on osmosis and diffusion has been proved correct. Contrary to this the experiment would probably be more reliable if we did it again.

In the new experiment I could have used some of the methods that I have already mentioned to make it more accurate.

Overall I am happy with the investigation and experiment and think that it went very well.