• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

Investigate the effect of salt concentration on the rate of water loss/gain by potato.

Extracts from this document...

Introduction

Investigate the effect of salt concentration on the rate of water loss/gain by potato. Plan: Investigate the effect of salt concentration on the rate of water loss/gain by potato. Hypothesis: I predict that the 0 M salt solution will make the potato gain weight because the water is at a higher concentration outside the potato so it moves in by osmosis. I predict that in the 0.2 M solution the potato will neither gain nor lose weight because I think that the concentrations of water in and out of the potato are the same. I predict that in the 0.4 M, 0.6 M, 0.8 M and 1.0 M solutions will lose weight because I think that the concentration outside the potato will be less concentrated than inside the potato so the water from inside the potato will move by osmosis. Background Knowledge: Osmosis - Osmosis is a special case of diffusion. Outside the cell in the animation, there is a low concentration of solute molecules and a high concentration of water molecules. Inside the cell, there is a high concentration of solute molecules and a low concentration of water molecules. The solute molecules can't diffuse out because the plasma membrane won't let them through. ...read more.

Middle

Adding solute - In fact when we add solute to water, the water molecules form a shell around each solute molecule. So this decreases the number of free water molecules that are able to exert a pressure on the membrane. Therefore, the water potential decreases. There is no solute in pure water. So pure water has the greatest water potential. Preliminary Study: Before starting this particular investigation I have conducted a similar experiment. The aim of the experiment was: To see how the mass of agar jelly affects the absorption of potassium manganate (VIII) solution. In the experiment I found that the potassium absorbed the furthest into the 0.5 cm3 cube of jelly, next into the 1 cm3 cube and last into the 2cm3 cube. Variables: VARY CONSTANT Salt concentration Control Amount of water Size of potato (length) Time (25 minutes) Temperature Type of potato Freshness of potato Apparatus Observations: I will make three repeats, recording the gain/loss in mass and length of the potato cylinders at the end and beginning of the experiment in six different salt concentrations. How I made up these concentrations is explained in the diagrams below. ...read more.

Conclusion

Mass @ start of experiment (g). Mass after (g). Mass gain/loss (g). Start length (cm). End length (cm). Length gain loss (cm). 0 2.3 2.5 0.2 3.3 3.4 0.1 0.2 2.4 2.3 -0.1 3.5 3.5 0 0.4 2.6 2.4 -0.2 3.5 3.5 0 0.6 2.4 2.1 -0.3 3.4 3.2 -0.2 0.8 2.4 2 -0.4 3.3 3.1 -0.2 1 2.2 0.7 -0.5 3.3 3 -0.3 3rd set of results: Salt concentration. Mass @ start of experiment (g). Mass after (g). Mass gain/loss (g). Start length (cm). End length (cm). Length gain loss (cm). 0 2.8 3 0.2 4.8 4.9 0.1 0.2 3.2 3.1 -0.1 4.7 4.7 0 0.4 2.8 2.5 -0.3 4.5 4.5 0 0.6 2.9 2.6 -0.3 4.7 4.6 -0.1 0.8 3 2.6 -0.4 4.7 4.6 -0.1 1 2.7 2.2 -0.5 4.8 4.6 -0.2 Average of results: Salt concentration. Mass gained/lost (g). Length gained/lost (cm). 0 0.183 0.1 0.2 -0.09 0 0.4 -0.243 0 0.6 -0.357 -0.133 0.8 -0.757 -0.133 1 -0.0497 -0.233 Analysis: From my two graphs of results I found very similar patterns, they both seem to lose length and mass mainly after the 0.2 M solution. At the first point 0 M they both gain in mass and length. They gain in mass because Evaluation: I only had one anomalous result Biology coursework. Niels Pedersen. ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our GCSE Green Plants as Organisms section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related GCSE Green Plants as Organisms essays

  1. Determine the water potential of potato tuber cell with the varying affect of solute ...

    I predict that this solution will cause the potato to loose the most amount of mass or the most water loss. I predict this is because now with this high concentration, the concentration of solute molecules is now very high outside the cylinder.

  2. The effect that different concentrations of salt solution in the water has on strips ...

    We also learnt that instead of measuring the length of the potato strip each time, mass would be recorded each time and the length of potato strip kept constant, as it is very hard to measure each potato strip to the exact mm accurately.

  1. An Investigation into Water Loss from Plants.

    of cells exposed to the air and very little transpiration will occur as there are very few stomata on the top surface of a leaf. Rack 4 will have minimal water loss therefore the mass should not change dramatically from the original weight.

  2. The factors affecting the rate of permeability in a cell membrane?

    It is a simple, cheap, reliable and accurate equipment it measure the temperature to +1�C and it is has a simple principle that works. Test tube This is used to hold the boiled water and beetroot. It is designed to fit the test tubes and is thermal so heat will

  1. Osmosis, I predict the mass of potato will first increase then start decreasing as ...

    In a graph showing the percentage change of potato mass cylinders in different concentrations of salt solutions, I think the graph will show that the mass will be high then slope down as the concentrations of salt solution get higher.

  2. Monitoring living organismsthe more concentration of salt there is, the less growth of the ...

    any of the seeds and how much it has grown by (measured by using a ruler). I would describe how the weather was like on that day, and if there was any growth. Also, I would inspect whether the leaves had necrosis or chlorosis occurring.

  1. The Loss of the Aral Sea

    The picture below is a typical example of how much of the area surrounding the Aral Sea has now become, with fishing trawlers left on the old sea bed to rot and remind people of more prosperous times. Many of the causes for the rises in these various diseases are

  2. Osmosis investigation. My prediction is that as the concentration of the solute increases, ...

    The results of the preliminary experiment are as follows: Molarity 0.00 0.25 0.50 0.75 1.00 Start mass (g's) 1.01 1.02 1.01 1.05 1.01 End mass (g's) 1.10 1.07 1.03 0.95 0.93 Variable control: 1. The potato used- this could mean different beginning solute concentration in the potato, rendering the results less reproducible.

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work