During the diffusion tube experiment I noted that firstly ammonium hydroxide was placed on to a piece of cotton wool. If you put plant cells into concentrated sugar solutions and look at them under a microscope you would see that the contents of the cells have shrunk and pulled away from the cell wall: they are said to be plasmolysed. After measuring and recording the masses of the cubes, they are immersed in water. Reassemble the apparatus, refill the measuring cylinder, and repeat from g to j with another concentration of hydrogen peroxide. Nitrates are washed out of a soil sample and are shown to reappear after a few days, using diphenylamine sulphate as a nitrate indicator.
In this lab, you will make cube shaped models to represent cells. However, the hypertonic solution for the cylinder actually decreased in the ratio. Osmosis is the passage of water from a region of high water concentration through a semi permeable membrane to a region of low water concentration. I also think it would have been useful to repeat the experiment another time and make more replicates to try and get the average results instead of only having one set of results to follow. Analysing Evidence and Evaluation: The graph was not available to view.
Explain why you were correct or wrong. Disclaimer This is a real A-level school project and as such is intended for educational or research purposes only. To cut potato cubes of different sizes, which have different surface area to volume ratios. A region of high concentration of water is either a very dilute solution of something like sucrose or pure water. Preliminary Work and Scientific Knowledge Osmosis is defined. For the mass, we had to be careful that all the potato chips were dried in the same way as this may have altered the reading. Step 4: To create the 40% salt solution.
Compute the volume of a cuboid also known as a rectangular prism with the dimensions 4cm by 13cm by 9cm. I think the graph will look like this but there will be no plasmolysed on my graph, as I do no expect my measurements to go that far. Apple, Apple crisp, Fruit 639 Words 4 Pages Rate of Osmosis Investigation Lab Title: A simple heading referring to your investigation Abstract: Write this section last! The smaller you make the potato the more surface area there is to absorb the food dye. Observations: Draw and write about your observations for all cubes. Usually, when the surface area is doubled it will double the rate of reaction.
Use the same units for all measurements. Conclusion: From the results obtained, I can conclude that the average gain or loss in mass of the potato chip is indirectly proportional to molarity. Background Information Hypertonic : Higher solute concentration less water than the cytoplasm which causes the cell to lose water via osmosis. Osmosis is the movement of water molecules from an area of high concentration to an area of low concentration Brown 1999. For example: a It is also impossible to precisely measure the size of gelatin block each time. The prediction could be made clearer.
Liver also contains catalase, but handling offal is more controversial with students and introduces a greater hygiene risk. Hypothesis If the potato is placed into a salt water solution hypertonic , then the surface-area-to-volume ratio will increase and the masses of the potatoes will decrease due to the need of maintaining homeostasis through diffusion of water molecules. Semi-permeable membranes are very thin layers of material which allow some things to pass through, but prevent others. The cells are filled with a red pigment and appear pink. Iodine solution reveals clear areas of starch-agar under the fruit Respiration 1 Oxygen uptake The inability of air from germinating seeds to support combustion 2 Carbon dioxide output The gas from germinating seeds turns limewater milky 3 Exhaled air 1 The last fraction of exhaled air will not support combustion 4 Exhaled air 2 Atmospheric air and exhaled air are bubbled simultaneously through limewater 5 Respiration in living organisms A manometer reveals uptake of oxygen by germinating seeds 6 Anaerobic respiration The gas produced by a yeast suspension from which air is excluded turns limewater milky 7 Energy release during respiration Germinating wheat is packed into vacuum flasks to see if there is any rise in temperature over a few days 8 Changes in mass during germination Wheat is germinated for about two weeks. I will measure each potato tube separately to ensure accurate measurements and carry out the procedure 3 times for each molarity tested.
Put the potato pieces into the cups according to its label. Now the rate is given by the change over time. Research question: What is the solute concentration of a potato? One would think there would be a linear pattern, but perhaps not. Health and safety checked, September 2008 Downloads Download the student sheet with questions and answers. As seen from the graph above, despite my hypothesis being correct, the trend in the percentage increase of mass was not a steady 1042 Words 5 Pages relationship between surface area : volume ratio and heat loss. This liquid or hydrostatic pressure works against osmosis.
The whole cubed potato however when cut open was red on the outside but potato colored in the middle and gained weight from when it was weighted on day 3. One of the aforementioned activities is Osmosis, or the movement of water across a selectively permeable membrane eventually establishing equilibrium on both sides of the concentration gradient Freeman 90. A block of gelatin which has been dyed with cresol red dye should be cut into blocks of the following sizes mm. A larger surface area means that there will be more catalase molecules coming in contact with the reacting substrate, hydrogen peroxide. Metabolism is the total of all the chemical processes that take place in the body. Which model has the largest surface area-to-volume ratio? Materials 2 thistle tubes, 2 big beakers, 4 tube clamps to fit iron stands. The first group also turned a greenish-brown color but it occurred along the edges more than in the center.
The tubes are illuminated or darkened 8 Gaseous exchange in pond-weed Leaves are enclosed in test-tubes containing hydrogencarbonate indicator. Cell, Cell wall, Osmosis 1523 Words 5 Pages How Do Different Factors Affect Osmosis Aim: To discover The Different factors that affect osmosis. If not then there may have been some variation in the age or flesh of the potato that might account for the weight gain. They were left for twenty minutes and the length. Mathematical description of the surface area is considerably more involved than the definition of arc length of a curve. I will be measuring and controlling many different variables, these include; - The dependent Variable Weight of potato chip Independent Variable Concentration of sucrose Control Variables consist of; - 1.