# Designing an Osmotic Potential Experiment with Potatoes

by janfalandgmailcom (student)

Designing an Experiment on Osmotic Potential

## Context

Osmosis is used throughout the kitchen in various countries. In France, aubergines and cucumbers are often soaked in salt to create a nicer texture, however chefs lack understanding of why this happens, as they would have forgotten about it after they finished school, they only know that it happens. Therefore, this experiment is designed to explain to the millions of chefs around the world why the water is “sucked” out of a vegetable when it is dipped into a salt or sugar solutions. I believe that having knowledge over the reason for something can open up new ways of thinking; this is why I think it is so important to explain the reason behind this phenomenon.

Famous chefs are also known to be under time pressure; for example, every cooking show on TV includes some sort of time pressure scenario, weather it is a ticking clock or waiting customers. For this reason, I would like to help these chefs save time by designing an experiment to determine the different lengths of time it takes a vegetable to be completely rigid or flaccid, this would help the chefs create the best texture in the shortest amount of time.

Therefore, I am setting up an experiment to test the minimum time required for a sucrose solution to create a desired result of either a flaccid vegetable or a rigid vegetable. I will also be setting up an experiment to show the mass change of the vegetables in each of the solution, and trying to find the osmotic potential of the vegetable.

## Hypothesis.

According to particle theory, water molecules are in constant motion. As they move, they hit the membrane and create a pressure against the membrane called the water potential. Solutions with a low water potential have a high solute (osmotic) potential. Therefore, solutions with a high water potential have a low solute (osmotic) potential.

The time it takes for a vegetable cell to reach a turgid or plasmolyzed state would not be more than one hour as this is the standard experiment time in the UK and around the world. Therefore, my hypothesis will be that it will not take any longer than one hour for the vegetable to reach a turgid or plasmolyzed state. For osmosis to happen as quickly as possible, the gradient should be as steep as possible; therefore I am expecting the saturated solution and the pure water to change the water-level of the vegetable fastest.

## Materials and Apparatus

For this experiment I will need little apparatus, the apparatus I will need will be the following:

• Seven jars, preferably one that can hold more than 0.5l of water.
• Potato, I will use one or more potatoes.
• Sugar, sugar will be used as the solute.
• Spoon, to stir the solution.
• Clock, to monitor the time.
• Still water, to be the solvent.
• Scale, to measure the mass of the potato and sucrose.
• Knife, to cut the potato.
• Measuring cylinder.

## Independent variable.

My independent variable will be ...