• Join over 1.2 million students every month
• Accelerate your learning by 29%
• Unlimited access from just £6.99 per month
Page
1. 1
1
2. 2
2
3. 3
3
4. 4
4
5. 5
5
6. 6
6

# Potato coursework

Extracts from this document...

Introduction

How does the concentration of a solution affect the osmosis rate of a potato Aim: The aim of my experiment is to see if the concentration of sugar solution I use will affect the rate of osmosis in potato cells. I will do this by recording data collected on the potatoes placed in different concentrations of sucrose. Research: Osmosis is a special kind of diffusion that only concerns the movement of water. If two solutions are separated by a semi-permeable membrane, which only allows certain sized molecules through there will be a net movement of the water molecules, from the less concentrated solution (the one with more water molecules), to the solution which is more concentrated (has more solute molecules). This is because as in ordinary diffusion the molecules move to even-out any difference in concentration. However, because of the semi-permeable membrane, which does not allow the larger solute molecules to cross; only the water molecules can move. The water molecules will continue to cross the semi-permeable membrane until equilibrium is reached, where the two solutions are of equal concentration. The greater the difference in the number of water molecules on either side of the membrane, the greater the water potential. Water potential is represented by the Greek letter ?. pure water has a water potential of 0kPa. As substances dissolve in the water, the water potential drops and becomes negative. ...read more.

Middle

spend in the sugar solution * Measuring cylinder - I will use a 2ml measuring cylinder so I can accurately measure different concentrations of the sugar solution * Paper towels -I will use these to dry the potatoes before they are weighed Preliminary The aim of my preliminary is to see which are the most suitable time and length to use in my main experiment. I will do the experiment as stated and use my results to come up with the suitable measurements. Results 5 minutes Length Weight before Weight after Difference 1cm 0.43 0.41 -0.02 2cm 0.81 0.78 -0.03 3cm 1.24 1.21 -0.03 4cm 1.55 1.51 -0.04 5cm 2.05 2.00 -0.05 10 minutes Length Weight before Weight after Difference 1cm 0.47 0.45 -0.02 2cm 0.86 0.82 -0.04 3cm 1.26 1.23 -0.03 4cm 1.66 1.57 -0.09 5cm 2.15 1.73 -0.42 15 minutes Length Weight before Weight after Difference 1cm 0.46 0.44 -0.02 2cm 0.92 0.87 -0.05 3cm 1.31 1.25 -0.06 4cm 1.83 1.77 -0.06 5cm 2.35 2.29 -0.06 20 minutes Length Weight before Weight after Difference 1cm 0.52 0.45 -0.07 2cm 0.84 0.81 -0.03 3cm 1.23 1.17 -0.06 4cm 1.61 1.55 -0.06 5cm 2.06 2.02 -0.04 From my results I have decided to use15 minutes to soak the potato in the sugar solution. I feel this is best as it produced consistent results and gave me enough time to set up the next experiment whilst the potato was in the solution. ...read more.

Conclusion

This could be down to any number of reasons including an inaccuracy when measuring out the solution. It could also be possible that the amount of time sI patted each potato piece to dry it could affect the end result. Although I can no be accurate when saying what affected my experiment I can guess at some of the factors that may have affected it. If I was to do the experiment again there would be a few things I would alter so I could increase the reliability of the results. Firstly I would put a lid on the test tubes. This is because water could evaporate out of the test tube causing the concentration to change. Another thing I would change is I would dry the potatoes in exactly the same way for the same amount of time for every experiment as a little bit of water left on the potato piece can affect its weight. The last thing I would change is the ruler I used. I would make sure the ruler had millimetres on it so I could make sure that each potato piece is exactly the same length. I think the results my graph produced are very reliable. They helped me come to a valid conclusion which I had predicted. To further my experiment I could vary the vegetables I use to see if the effect of concentration is the same on them. Examples of vegetables I could use are swede or parsnip, as these vegetables have similar properties to the potato. Clair Kidd-Stanton, 2107 Page 1 The George Ward School ...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 Exchange, Transport & Reproduction 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

# Related AS and A Level Exchange, Transport & Reproduction essays

1. ## Sand Dune Succession Coursework

5 star(s)

Succession takes place as the vegetation develops and if there is lack of vegetation then succession will not occur. Weather If it is raining then the water content of the soil will increase, therefore increasing the likelihood of succession occurring.

2. ## Investigate the water potential of celeriac.

5 star(s)

Join the points with straight lines and determine the molarity at which the percentage change in mass is zero - where the line intersects the x-axis. Using a calibration graph - the x-axis = concentration of sucrose and y-axis = water potential - calculate the water potential of celeriac.

1. ## The Effect Of Temperature On The Permeability Of The Cell Membrane

3 star(s)

At 60 degrees Celsius the gradient of the graph decreases. So at about 60 degrees Celsius, this relates to when the lipids in the cell surface membrane begin to break down producing holes in the membrane through which the red pigment anthocyanin leaks out From 0-40 degrees Celsius, the pigment

2. ## What is Type 1 diabetes

3 star(s)

After the pregnancy, it is important to get examined once a year in order to find out if the diabetes has developed again. The likelihood of developing diabetes later in life can be reduced by: avoiding becoming overweight eating a healthy diet exercising regularly not smoking (this will benefit both the foetus and mother).

1. ## The comparison of antibacterial properties of herbal products and standard antibiotics

5 star(s)

Prediction: The herbal products will be more effective against the growth of bacteria compared with the standard antibiotics. Equipment additions: The equipment list will stay the same but the amount of agar plates used will be doubled; two pieces of equipment will be added.

2. ## Effect of Caffeine on the Heart Rate of Daphnia

3 star(s)

is one of the factors that affects the heart rate of it. Prolong exposure of the Daphnia to the microscope light will overheat the Daphnia. To prevent the Daphnia (water flea) from overheating, the microscope light should be turned off between observations and a heat sink should be used.

1. ## Investigating Water Potential Of Potatoes.

Write the final weight in the final weight column in the table. 11. Repeat step 10 for the rest of the cylinders DIAGRAM SAFETY Due to this experiment having sharp instruments to handle, safety will have a very important role to play.

2. ## Osmosis in Potato cells

scalpels and not to point them or carry them around as they could injure, the white tile was placed underneath to avoid cutting oneself. * Students were warned that if any glass breakages were to occur, that other students were warned and the breakage swept away immediately into a safe container to be disposed of.

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