We will try and get the measurements of the potatoes as accurate as possible for every single potato, evenly cutting the potato pieces, and making a record of the length to the nearest millimetre. .
But I believe one of the most important steps in the fair testing is to make sure that the potato is fully covered by the solution. This is because the potato should fully submerge, by having total contact with the solution. So I will push the potato to the bottom making sure there is at least 2-3 cm of sucrose solution above the potato. .
When using the balance, we will make sure that the balance is reading zero with the small foam bowl, before we put the potatoes on it. This is so that we don't get a false reading, with the weight of our potato with the reading it had before. And after the experiment, we will measure the potatoes that should be dried as possible, and weigh it the same way, taking the reading to the nearest 2 decimal places and making sure there at the same temperature.
And we will also be reading the measurements of the measuring cylinder by reading the bottom of the meniscus.
In this experiment there should only be two changing variables: 1: Different concentrations of sugar solution. 2: Changing weight of the potato samples. To keep these two variables fair in the experiment I must:.
1: Keep the potato samples the same length (5cm). This is because if one potato sample is 4cm long and one is 6cm long then the 6cm long sample will have a larger surface area and osmosis will occur much more quickly. Also I will try and keep the surface area the same as if there is a bigger surface area than other potatoes more osmosis will take place.
2: Use the same potato. This is because many factors due to the potato may affect the experiment. For example the age, species e.g. King Edward, size and any imperfections in the potato can be kept to a minimum.
3: Stop the evaporation of any of the molar solution.