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

Studying the Effect of Salt on Cress Germination

Extracts from this document...

Introduction

PLANNING Initial Method 1. Prepare 8 sterile Petri dishes with a perfectly fitting circle of cotton wool and filter paper, this will sit on top of the wool 2. A control dish must also be set up using the same steps as above 3. Weigh out 8 different salt measures, at 0.25, 0.5, 0.75, 1, 1.25, 1.5 and 1.75 4. Measure out 8, 50ml beakers of distilled water 5. Add the one measure of salt into a beaker (1 beaker for each weight) and stir until the salt is dissolved and cannot be seen 6. Add one drop of Plant nutrient growth (e.g. baby bio) to each solution 7. Add each solution into individual Petri dishes which were made up earlier on, make sure the cotton wool and filter paper are allowed a small amount of time to absorb as much water as possible before the next step 8. Add 10 Cress seeds to each of the 8 solutions and place the lid on the dish 9. Place the dishes in are area which is well lit by natural light 10. Check the dishes each day for a week and top up each dish with the same solution if it is becoming dry, add the same amount to each dish (record what you add) ...read more.

Middle

I controlled the samples of cress water and salt by ensuring they were all measured correctly and from the source. I used the same type of cress and salt which were taken from one batch. The water was also all used from the same bottle. Table of results (preliminary) SALT (grams, g) SALT CONCENTRATION (%) NUMBER OF SEEDS GERMINATED (%) 0.25 0.5 100 0.5 1 70 0.75 1.5 60 1 2 40 1.25 2.5 0 1.5 3 0 1.75 3.5 0 0 0 100 Figure 2 - preliminary results The results I have recorded are sufficient to use in a spearman rank coefficient data test as I am looking for a correlation and trend and have taken a suitable amount of repeats and tests to gain a result from the stats test. I also have no anomalies in my original results as they all appear to follow a trend Statistical Data Test - Spearman Rank Coefficient For my main experiment, I have chosen to analyse the results using a Spearman's Rank Correlation Coefficient test. This should allow me to assess whether there is significant correlation between the concentration of salt (NCaL) and the germination of seeds. This test is appropriate as I am taking readings for 8 different concentrations, and both of the variables recorded (germination % and concentration) ...read more.

Conclusion

11. Repeat this process again so that you run two sets of 8 salt concentrations OBSERVING AND RECORDING Table of Results SALT (grams, g) SALT CONCENTRATION (%) NUMBER OF SEEDS GERMINATED (%) 0.05 0.1 92.5 0.2 0.4 65 0.35 0.7 40 0.5 1 20 0.65 1.3 12.5 0.8 1.6 0 0.95 1.9 0 0 0 97.5 Figure 7 - Main investigation results The above results show a general correlation indicating that increased salt concentrations reduce the germination of cress seeds, however I will analyse this later Statistical Data Test - Spearman Rank Coefficient Category Data 1 Rank R1 Data 2 Rank R2 d = (R1 - R2) d2 1 0 1 97.5 8 -7 49 2 0.1 2 92.5 7 -5 25 3 0.4 3 65 6 -3 9 4 0.7 4 40 5 -1 1 5 1 5 20 4 1 1 6 1.3 6 12.5 3 3 9 7 1.6 7 0 1.5 5.5 30.25 8 1.9 8 0 1.5 6.5 42.25 n 8 Sum 0 167 Figure 8 - Main investigation statistical test The spearman rank correlation coefficient equalled - 0.98 and the critical value were 0.64 giving a significant correlation (which was negative) therefore disproving my null hypothesis "salt has no effect on the germination of cress seeds." The results show that the larger the salt concentration gets the lesser the cress seed germination is. INTERPRETATION AND EVALUATION Figure 9 - Main Investigation results graph. ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our AS and A Level Energy, Respiration & the Environment section.

Found what you're looking for?

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

Here's what a teacher thought of this essay

4 star(s)

A well conducted investigation with clearly identified variables. Appropriate statistical analyses successfully carried out but their interpretation should refer to levels of significance, chance and probability.

4 Stars

Marked by teacher Adam Roberts 25/10/2014

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 AS and A Level Energy, Respiration & the Environment essays

  1. Marked by a teacher

    effect of temperature on the rate of respiration in yeast

    5 star(s)

    A redox reaction has taken place. After a second hydrogen carrier, the hydrogen splits in to hydrogen ions and electrons. The hydrogen ions remain in solution in the mitochondrial matrix, whilst the electrons are passed along a series of electron carries. This makes energy available which is used to convert ADP + Pi to ATP.

  2. Marked by a teacher

    An investigation into the effect of different sugars on respiration in yeast.

    5 star(s)

    Maltose http://www.mansfield.ohio-state.edu/~sabedon/biol1025.htm#disaccharide Maltose is a disaccharide and a reducing sugar. The chemical formula for maltose is C12H22O11. It is formed by two glucose molecules which are joined together at carbons 1 and 4 by a glycosidic bond. Lactose http://sci-toys.com/ingredients/lactose.html Lactose is a disaccharide that naturally occurs in both human and cow's milk.

  1. Marked by a teacher

    Effect of nitrate concentration on the growth of Duckweeds

    5 star(s)

    I had placed the duckweeds on a white tile whilst picking the ones I used, so that I was able to pick out the similar coloured fronds more clearly against the white background. By using a magnifying glass I was able to make sure that the duckweeds I picked were

  2. Marked by a teacher

    To make sure we have plenty of energy in the future, it's up to ...

    4 star(s)

    They were first developed in the 1950s for use on U.S. space satellites. They are made of silicon, a special type of melted sand. When sunlight strikes the solar cell, electrons (red circles) are knocked loose. They move toward the treated front surface (dark blue colour).

  1. Marked by a teacher

    Biology coursework investigation: Comparing the length of ivy leaves (Hedera helix) in areas of ...

    4 star(s)

    The rootlets allow the plant to climb trees, walls, and other vertical structures. The vine attaches to surfaces but does not penetrate through mortar or tree bark, thus it is not considered to be a parasite (Elliott, 1995). Hedera helix thrives in dark, moist forest conditions but can climb to

  2. What effect does substrate have on respiration in yeast?

    This should be carried out for all five substrates. These controls are needed to prove that it is the substrates given to the yeast solution that causes the yeast to respire and produce carbon dioxide. They would also demonstrate that yeast by itself or just the substrate can not produce

  1. Cycles in Biology.

    It releases the chemical messenger Follicle Stimulating Hormone Releasing Factor (FSH-RF) to tell the pituitary gland in the brain to secrete Follicle Stimulating Hormone (FSH) and a little Leutenising Hormone (LH) into the bloodstream, which cause the follicles to begin to mature. The maturing follicles then release another hormone, oestrogen.

  2. Effects of exercise on tidal volume and breathing rate

    decrease in end-expiratory lung volume, and the work of breathing during exercise is sustained by activity of both inspiratory and expiratory muscles. When exercising the Tidal Volume increases because your breathing at a faster rate and your muscles are using up the oxygen at a quicker rate hence a need

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