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Biology63 views·Updated Jun 1, 2026·2 pagesUnderstanding Osmosis Practical: GCSE AQA Guide
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Setting Up Your Osmosis Experiment
You'll be investigating how osmosis works by watching water move in and out of potato cells. Osmosis is simply the diffusion of water from a weak solution to a strong solution through a partially permeable membrane - think of it as water trying to balance things out.
Your independent variable is what you're changing - the concentration of sugar solution. The dependent variable is what you're measuring - how much the potato's mass changes. Keep everything else the same: temperature, potato size, volume of solution, and timing.
Start by cutting potato cylinders with a cork borer or knife, making them roughly the same size. Weigh each piece carefully and record the mass. Then prepare your sugar solutions at different concentrations: distilled water (0%), 0.2 mol/dm³, 0.4 mol/dm³, and 0.6 mol/dm³.
Top Tip: Pat the potato dry before weighing to get accurate results - surface moisture can mess up your measurements!
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Understanding Your Results
Place each potato piece in a different solution and wait 30 minutes. After removing them, gently pat off surface moisture and reweigh. Calculate the percentage change in mass to see what's happened.
In distilled water, your potato gained mass because water moved into the cells through osmosis. The potato cells had a higher concentration of dissolved substances than pure water, so water rushed in.
In strong sugar solutions, the potato lost mass as water left the cells. The sugar solution outside was more concentrated than inside the potato, pulling water out through the cell membranes.
Remember: Water always moves from where there's less dissolved stuff to where there's more dissolved stuff - it's trying to even things out!
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Biology63 views·Updated Jun 1, 2026·2 pagesUnderstanding Osmosis Practical: GCSE AQA Guide
P
Poppy@poppy_s
Ever wondered why chips go soggy when you put salt on them? It's all down to osmosis - the movement of water through cell membranes. This practical investigation shows you how to test osmosis using potatoes and different sugar solutions.
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Setting Up Your Osmosis Experiment
You'll be investigating how osmosis works by watching water move in and out of potato cells. Osmosis is simply the diffusion of water from a weak solution to a strong solution through a partially permeable membrane - think of it as water trying to balance things out.
Your independent variable is what you're changing - the concentration of sugar solution. The dependent variable is what you're measuring - how much the potato's mass changes. Keep everything else the same: temperature, potato size, volume of solution, and timing.
Start by cutting potato cylinders with a cork borer or knife, making them roughly the same size. Weigh each piece carefully and record the mass. Then prepare your sugar solutions at different concentrations: distilled water (0%), 0.2 mol/dm³, 0.4 mol/dm³, and 0.6 mol/dm³.
Top Tip: Pat the potato dry before weighing to get accurate results - surface moisture can mess up your measurements!
2
of 2Sign up to see the content. It's free!
- Access to all documents
- Improve your grades
- Join milions of students
Understanding Your Results
Place each potato piece in a different solution and wait 30 minutes. After removing them, gently pat off surface moisture and reweigh. Calculate the percentage change in mass to see what's happened.
In distilled water, your potato gained mass because water moved into the cells through osmosis. The potato cells had a higher concentration of dissolved substances than pure water, so water rushed in.
In strong sugar solutions, the potato lost mass as water left the cells. The sugar solution outside was more concentrated than inside the potato, pulling water out through the cell membranes.
Remember: Water always moves from where there's less dissolved stuff to where there's more dissolved stuff - it's trying to even things out!
We thought you’d never ask...
What is the Knowunity AI companion?
Our AI Companion is a student-focused AI tool that offers more than just answers. Built on millions of Knowunity resources, it provides relevant information, personalised study plans, quizzes, and content directly in the chat, adapting to your individual learning journey.
Where can I download the Knowunity app?
You can download the app from Google Play Store and Apple App Store.
Is Knowunity really free of charge?
That's right! Enjoy free access to study content, connect with fellow students, and get instant help – all at your fingertips.
Most popular content in Biology
9Most popular content
9Can't find what you're looking for? Explore other subjects.
Students love us — and so will you.
4.6/5App Store
4.7/5Google Play
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan SiOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha KlichAndroid user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
AnnaiOS user