Osmosis Coursework

Essay by clownHigh School, 11th gradeA, March 2006

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Investigating the water potential of Potato tissue.

Introduction:

In this investigation I aim to discover the water potential and solute potential of potato tissue. I will accomplish this by placing potato pieces of equal size into varying concentrations of sucrose solution and examining the percentage change in mass. Then I will plot my results onto a graph and work out the intercept at which the line of best fit crosses the x-axis (concentration of sucrose solution). This will give me the water potential of the potato tissue, i.e., the point at which there is no increase or decrease in mass and the cell is in equilibrium.

Preliminary Investigation:

Introduction:

I have conducted a preliminary investigation to examine the mass change of potato 'chips' in 5 different sucrose solutions. This will give me first hand research to help base my Hypothesis. IT would also inform me in terms of which Sucrose concentrations to use in my main investigation, and I can alter any variables accordingly if any problems occur with the ones I am using, i.e.

Potato strip size, amount of different concentrations, volume of concentration and apparatus used.

Apparatus:

Apparatus

* One potato.

* One set of cork borers.

* Two syringes.

* Six test tubes.

* A test tube rack.

* A ceramic cutting tile.

* A sharp cutting knife.

* Distilled water.

* Sucrose concentration 1 Mole.

* A balance to measure mass.

* A stop watch.

Notes:

* The cork borers insure that the surface area of each potato strip is kept as standard as possible, and the width is exactly the same.

* The ceramic cutting tile prevents the underlying surface from getting damaged and a ruler ca be used to cut the potato strips for more accuracy.

Method:

* Using the number 5 cork...