• 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)

    When an electron passes from a carrier at a higher energy level to one that is lower, energy is released. Some energy is lost as heat. At the end of the chain, the hydrogen's and electrons join with oxygen to form water and so we can see the role of oxygen.

  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)

    all in similar sizes and also were healthy by not having any damaged fronds or rootlets. I picked out 18 duckweeds with four fronds each, so that one duckweed could be placed into each of the wells in the tray.

  2. Marked by a teacher

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

    4 star(s)

    Today, the wind is also used to make electricity. Blowing wind spins the blades on a wind turbine -- just like a large toy pinwheel. The blades are attached to a hub that is mounted on a turning shaft. The shaft goes through a gear transmission box where the turning speed is increased.

  1. 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

  2. Cycles in Biology.

    Eutrophication alters the way in which the nutrient cycles occur. Natural eutrophication is the process by which lakes gradually age and become more productive. It normally takes thousands of years to progress. However, humans, through their various cultural activities, have greatly accelerated this process in thousands of lakes around the globe.

  1. The Pancreas is a large gland that forms part of the Endocrine System, but ...

    * Vomiting * Fever and * Rapid Pulse In severe cases of Acute form, blood pressure can be affected and dehydration can occur. With Chronic Pancreatitis, this will occur when Digestive enzymes attack and destroy the Pancreas itself and the nearby tissues.

  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