Effects of Osmosis and Diffusion on Pears in Different

Topics: Osmosis, Concentration, Chemistry Pages: 5 (1723 words) Published: June 11, 2013
1. Provide aim and background information
1.1 Diffusion is the process which molecules dissipate into a solution evenly over a period of time. An example is putting sugar in your coffee, after a while if you don't mix the solution, the sucrose will over time, go through the process of diffusion and be distributed throughout the coffee. Osmosis is movement of H2O molecules passing through a permeable cell membrane to the less concentrated solution, eventually to reach an equivalent number of molecules on both sides of the cell membrane. 1.2 The important factors in the process of diffusion and osmosis is H2O being present with soluble molecules that are small enough to be absorbed through the cell membrane to then be evenly distributed throughout the object. Temperature is another important factor which must be considered. Generally the higher the temperature, the faster solutes can dissolve into the solution and a higher amount of solutes are able to be dissolved into the solution. This is because an increase in temperature means an increase in kinetic energy, resulting in molecules moving faster, and molecules going through osmosis and diffusion faster. 1.3 The aim of this investigation is to see the rate of diffusion and osmosis in different sucrose concentrates, measured by weighing pears before and after they have been submerged in sucrose solutions of different concentrations. 1.4 The projected result is that according to the percentage of sucrose in the concentration, the pear will absorb more sucrose through the process of diffusion and osmosis and will be measured by weighing the prepared fruit before and after, to show that sucrose has been absorbed by the fruit. I also expect the pear to gain weight through absorbing water, in the less concentrated solutions of sucrose. 1.5 The projected outcome by my hypothesis was close to being correct. The only result I did not take into account was the pear and solution to be isotonic, and there to be no change in the weight of the pear. I expected as the sucrose levels to go up, the pear weights after would keep increasing in weight, not to get higher, then drop back to lower percentage of weight increase. 2. Describe the experimental method and design supporting the investigation 2.1 The required apparatus for this experiment is:

* a knife and cutting board
* slices of pear of the same size weight and shape
* beakers to soak the pears in
* a scale that is accurate to two decimal places
* 5 solutions of H2O and sucrose of different concentrations at 5%, 10%, 15%, 20%, 25%. 2.2
1. The pear was prepared into uniform shapes and weights. 2. The solutions made into the required concentrations and put into beakers. 3. The pieces of pear were placed into separate solutions for an hour. 4. After soaking, the pear was taken out and weighed to measure the results of the osmosis and diffusion.

2.3 Risk assessment as follows:
Risk| Hazard| Precaution|
Cutting yourself| Sharp knife| Take caution not to cut yourself| Burning yourself| Hot water| Care must be given|
A knife is required in preparation so caution is required to not cut yourself. The water may require to be heated to dissolve the sucrose in so care must be given not to spill heated water on yourself. 2.4 Pears may be swapped out with any other fruit or vegetable to use in this experiment for a slight variation of it. Sucrose solutions may also be changed to different concentrations. 2.5 The variables to this experiment would be if the pear pieces were different shapes and weights, this would make the results vary too much for any accurate results. This must be prevented by weighing all the pieces to make sure they are all very close to the same shape and weight. Temperature may also have a part in the process, so it is best to keep the solutions and pears to approximately the same temperature. 3. Report and interpretation of results

3.1 Pear Piece Weight Before Being...
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