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

Osmosis Investigation

Extracts from this document...

Introduction

Osmosis Investigation Aim: The aim of this investigation is to explore osmosis in potato cells and find approximately the concentration of sucrose within potato cells by measuring the change in mass of potato chips when immersed in different sucrose solutions for a set period of time Introduction: Osmosis happens in the cells of all living things. It is a simple process where water molecules diffuse from one cell to another through the partially permeable cell membrane. (the membrane has tiny holes in it that allow simple molecules, such as water, to pass through) During the process of osmosis, water moves between higher and lower concentrated solutions of either saline or a sugar solution until water molecules are evenly distributed between the two (or more) solutions (until they reach equilibrium), and in the case of cells, when the cells are of equal dilution. This movement of water is called diffusion. In the example below, there are two unbalanced solutions separated by a partially permeable membrane. Solution A has a higher concentration of sugar molecules than Solution B. As the process of osmosis begins, the water molecules from solution B begin to move into solution A, seen below. After time, enough water molecules have moved to achieve equilibrium, and the process stops. ...read more.

Middle

1 sharp scalpel ( to cut chips to size) 1 large potato (to take chips from) 6 sugar solutions of varying concentrations; 0%, 10%, 20%, 30%, 40% and 50% (to place potato chips in to find concentration) 1 stop clock that will time 1 hour (to keep amount of time in solution the same for each chip) 1 test tube rack (to hold the test tubes during the experiment) 6 soft tissues of the same make (to remove excess solution from the potato chips before their mass is measured) 6 beakers (for mixing the different solutions in) 6 30ml measuring cylinders ( to measure amount of solution each chip is placed in) 1 pair of tongs (to remove chips from solutions) Method: 1.Prepare a range of sugar solutions of varying concentrations; 0%, 10%, 20%, 30%, 40% and 50% in separate beakers to prevent contamination. 2. Take 6 sections of potato using the 10mm borer, remove skin 3. Carefully cut each section to 50mm in length using the scalpel & ruler 4. Measure mass of each chip with top pan balance to ensure each is almost the same. Any major differences mean the chip must be discarded and a fresh one made. 5. Record your mass readings for future use in a results table. ...read more.

Conclusion

6. Place the test tubes in a test tube rack and carefully measure out 25ml of each solution and pour it into the relevant tube. 7. Place the potato chip in the tube containing the 50% solution. Start a stop clock as the chip enters the tube. 8. Leave the chip for one hour. 9. Carefully remove the chip with tongs, remove any excess moisture with a soft tissue and measure the mass immediately with the top pan balance. Quickly record the result. 10. Place the chip into the test tube containing the 0% solution as quickly as possible to prevent evaporation and start the stop clock. 11. Leave the chip for 1 hour. 12. Carefully remove the chip with the tongs, remove any excess moisture with a soft tissue and measure the mass with the top pan balance. Record the result. 13. Repeat experiment 3 times to check your findings. This preliminary experiment would determine whether or not osmosis is reversible and a full investigation into this matter could then be performed. Other than those things, not much else could be changed, as the results were very reliable due to the extensive precautions taken to make it a fair test. In the future yet more experiments could be performed to learn more about osmosis, such as seeing how time affects osmosis or how surface area exposed to solution affects rate of osmosis. Also, different vegetables could be used to examine variations in sucrose concentration in different species. ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our GCSE Life Processes & Cells 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

See related essaysSee related essays

Related GCSE Life Processes & Cells essays

  1. Marked by a teacher

    Investigating the effect of Sucrose Concentration on the Rate of Osmosis in Potato Chips.

    5 star(s)

    The water shall exert a high pressure from the inside of the cell onto the outside of the cell (where the pressure is low). The water will osmose out of the potato chips' cells and into the sucrose concentration and the mass of the potato chip, in grams, will decrease.

  2. Marked by a teacher

    To investigate how varying the concentration of sucrose solutions affects the rate of osmosis ...

    3 star(s)

    This meant that the isotonic point of the potato sap had been attained and the concentration of water at both sides was equal. This observation matched the prediction I had made earlier as the isotonic point of the cell sap is greater than 0.125M.

  1. Osmosis Investigation

    When the concentration difference is greater, we say the concentration gradient is steeper. Size of the Molecules: When a molecule is heavier, then it will obviously take a greater deal of time to diffuse across the semi permeable membrane as the molecules speed is decreased.

  2. Osmosis investigation

    -18x potato chips (20mm/2cm) -1x Scales (sensitivity to be 2 d.p.) -1x Cutting tile -1x Beaker with 150ml3 of water -1x Beaker with 150ml3 of sucrose solution -1x Pipette for water -1x Pipette for sucrose -1x Cork borer size 4 -1x Cork borer size 5 -1x Ruler -1x Results table

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