Aim of the investigation
The aim if the investigation is to find out how different concentrations of sucrose solution affects the size, weight and turgidity of identical potato chips.
Preliminary work
We set up some basic tests to see if the theory of osmosis was correct. We found that the general trend was that if there was a stronger sugar content in the water outside the potato chip, the chip would decrease more. We also found that if the chip was in low sucrose concentration conditions, it became larger, sucking up the surrounding water and increasing it’s turgidity.
We also changed the many variables that we intended to keep the same, in order to determine which set up would yield the most dramatic results. These included-
- Temperature
- Volume of solution
- Size of chip (length and mass)
- Type of potato
- Sizes of equipment
- Time potato chip is immersed in water
- Range of the concentration of sucrose
We concluded that the experiment should be conducted at room temperature (due to the fact that this is constant and easy to maintain), use 100cm3 of water, use a King Edward potato chip that is 10x10x30mm, in a boiling tube for 45 minutes. The sucrose concentration will vary from 0m (distilled water) to 1m.
Apparatus list
- x 11 10x10x30mm King Edward potato chips
- 1100cm3 distilled water (100cm3 for each tube)
- Tissue/ kitchen paper (to remove excess water)
- x11 boiling tubes (1 for each potato chip/easily holds chip)
- 1 test tube rack (11 tube capacity)
- Sugar
- Scalpel (to cut potato)
- Timer (to time experiment)
- Stirrer (ensure sucrose is mixed well)
- Syringe with 10cm2 capacity(to measure liquid
- Permanent marker pen (to mark boiling tubes
- Tweezers (to remove chips)
The sucrose strength of each boiling tube will increase in increments of 0.1M e.g. first test tube will be 0M, next one 0.1M, 0.2M etc..
This is a diagram of how the experiment will look:
Variables
As I mentioned earlier, the variables in this experiment are: Temperature, Size of chip, Time chip is immersed in water, type of potato, volume of solution and concentration of sucrose in the water. All these factors will be kept the same, apart from the sugar concentration. This will make it a fair test.
Method
1. Gather all apparatus, sugar, water and potato
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Dilute 1M of the sucrose-water into increments of 0.1 by adding 10ml of 1M, 90ml water to make 0.1M, 20ml 1M, 80ml water to make 0.2M and so on… Stir well
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Cut potato into accurate 10x10x30mm chips and weigh to ensure they are equal (weight = xg)
- Measure 100cm3 of the different strengths of sucrose-water solution and pour into boiling tubes, label as in diagram
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Add potato chips at the same time and start timer immediately.
- Leave chips for 45 minutes.
- When 45 minutes is up, remove chips quickly and lightly dab on tissue/kitchen paper to remove excess water.
- Measure and weigh chips, ensuring they do not get mixed up.
- Note down results on a table similar to this:
