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How the concentration of salt-water affects the rate of osmosis.

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Introduction

How the concentration of salt-water affects the rate of osmosis. Aim: To find out how the concentration of salt-water affects the rate of osmosis in a potato. Prediction: My prediction is when the concentration of salt-water gets higher the mass of the potato will get smaller. The reason for this is because when the concentration of salt is low the concentration of water will be high. The water moves from a high concentration to a low concentration. The potato has a low concentration of water so the water passes through the semi permeable membrane and the potato gains water through osmosis, increasing the mass of the potato. If the concentration of salt is high then the concentration of water will be low. ...read more.

Middle

* The size of the potato because if they are different sizes the potato may gain more water because it can hold more making the test unfair. * The concentration of the salt in the water because the salt will affect how much water will move in or out of the potato. The apparatus I will need is: * Cups. * Different concentrations of salt-water. * A potato. * Something to cut the potato. * Electronic scales. * Coloured pins. * A ruler. * Measuring cylinder. This is what my experiment will look like. The concentration of the salt in the water is the one variable I am going to change because I want to find out how the concentration of salt-water affects the rate of osmosis. ...read more.

Conclusion

I will use five different concentrations of salt-water, distilled water, 0.25 M, 0.5 M, 0.75 M and 1 M concentrations of salt-water. The calculation I will do are the percentage increase in mass because they were not all the same mass when the were cut to size and to keep the test fair I will use the percentage increase to help me find out the relationship between the concentration of salt-water and the rate of osmosis. The graph I will plot will be a line graph to help show the relation ship between the two and to make the results clearer to see. I will make the results accurate and reliable by taking the average percentage increase from the results. I will take this by adding the three results from the one concentration and divide that by the number of results, which are three. ...read more.

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