2A_Leek+Experiment

__**Title**__ Leek Experiment

__**Aim**__ The aim of this experiment was to estimate the approximate osmotic concentration of the leek stem cells. __**Hypothesis**__ The leek will curve outwards the most and also increase in mass the most in the distilled water solution, followed but the leek in the 1% salt solution. This is as the solutions are hypotonic. The leeks in the 2% and 4% salt solution will not curve any way nor will it gain any weight. This is as the solutions are isotonic. The leek in the 7% salt solution will carve in and gain some weight. The leek in the 10% salt solution will curve in the most and also gain the most weight. This is as the 7% and 10% salt solutions are hypertonic solutions. I estimate that the osmotic concentration of the leek is about 97%.

__**Independent variable**__ The water potential of the solution the leek is put in.

__**Dependent variable(s)**__ The length of the inner cortex. The mass of the leek.

__**Constant variables**__ Amount of solution in the beaker. Starting length of the leek. Thickness of the leek. The osmotic concentration of the leek. Amount of time soaked in solution.

__**Materials**__
 * Ruler
 * Razor blade/scalpel, white tile
 * 5 petri dishes
 * Forceps
 * Distilled water
 * 1%, 2%, 4%, 7%, 10% salt solution
 * Chinese leeks (allium tubersosum)
 * Stop watch
 * Thread
 * Labels

__**Methods**__ Procedure
 * 1) Cut the inflorescence stalk of the Chinese leek to obtain a length of 3 cm and weigh.
 * 2) Cut the strip longitudinally as shown in the diagram below to obtain 4 equal quarters. Repeat till you have obtained 6 strips.
 * 1) Place one strip in a Petri dish of distilled water, one each in 1%, 2%, 4%, 7% and 10% salt solution.
 * 2) After 25 minutes, record the **length** of the inner surface and weigh. **Draw** the results in a table and graph. Explain how the length was measured.

__**Results**__ Quantitative results

LENGTH (cm) |||||||| MASS (g) || Before || After || Diff || % Diff || Before || After || Diff || % Diff || Distilled water || 3.0 || 3.5 ||  +0.5 ||  +16.7% ||  0.13 ||  0.18 ||  +0.05 ||  +38.5% || 1% salt solution || 3.0 || 3.5 ||  +0.5 ||  +16.7 % ||  0.18 ||  0.18 ||  0.00 ||  0.00 || 2% salt solution || 3.0 || 2.9 ||  -0.1 ||  -3.33% ||  0.20 ||  0.19 ||  -0.01 ||  -5.0% || 4% salt solution || 3.0 || 2.8 ||  -0.2 ||  -6.67% ||  0.20 ||  0.18 ||  -0.02 ||  -10.0% || 7% salt solution || 3.0 || 2.8 ||  -0.2 ||  -6.67% ||  0.18 ||  0.12 ||  -0.06 ||  -33.3% || 10% salt solution || 3.0 || 2.6 ||  -0.4 ||  -13.3% ||  0.15 ||  0.13 ||  -0.02 ||  -13.3% ||

__**Data analysis:**__ The graphs indicate that the mass and length loss is a downwards curve.

__**Conclusion:**__ The osmotic concentration of the leek based on the graph is 96.3%. I am 0.7% off from my mark.