Osmosis

AIM: to test the theory of osmosis we will put several equal potato slices in different concentration of sucrose solution and observe the changes in the weight of the potato

EQUIPMENT: potato, potato chips, sucrose solution 0-10, 5 beakers and scales to weight the potatoes

PREDICITON: the potatoes will weight more in different solutions after 10 minutes in the sucrose.

THEORY: osmosis is the name to describe the diffusion of water through a partly permeable membrane from a high to low concentration of water osmosis is just an special kind of diffusion because only the water molecules and their movement we are considering. This special kind of diffusion only occurs when a partially permeable membrane separates 2 solution, so osmosis is the movement of water through a partially permeable membrane from a region of high water concentration to a region of low concentration, the water is said to move down a concentration gradient.

If a potato chip is put into a beaker containing water, then after a while the chip weighs more than it did at first and the chips has become firmer. Water has moved into the chips by osmosis but when a similar chip is put into a beaker of sugar solution after a while the chip has lost weight. And it is very soft because water has moved out the chip into the sugar solution by osmosis; dialysis tubing can be used in a similar way dialysis tubing is a partially permeable membrane. Osmosis is a very important process it enables plants to take in water through their roots because there will usually be a lower concentration of water inside the cells of the roothairs than outside in the soil.

METHOD

1. Collect equipment

2. Pore the different strengths of solutions into different beakers and label them make sure you pore to 50ml

3. Cut 5 pieces of potato and make sure they all have the same weight

4. Draw table to plot results of the measurements

5. Put each potato piece in the beakers and leave for 10 minutes

6. Take out the potato chips after the 10 equal minutes and plot down the weight of the slice on the graph

7.