The experiment will be working with diffusion and osmosis; it will test if the starch will travel through the semi permeable membrane (dialysis tube) causing osmosis.
Diffusion is when a substance is highly concentrated turns into a lower concentration, and is evenly distributed throughout. An example of diffusion is when you cook and the smell of food flows until it in dynamic equilibrium; which is the even distribution of the substance. Osmosis is the movement through a semi permeable membrane into another area of higher concentration. Osmosis moderate’s diffusion, it will equalize the concentrations of solutions on both sides of membrane. A semipermeable membrane is a selective membrane that will block some of the larger molecules …show more content…
The difference between the variable in the control and the experimental is the variable that is being tested. In this experiment the
Variables Control Group Experimental Group
Iodine Time Amount of Iodine
Starch Solution Starch solution
Temperature of water Temperature of water
Dialysis tubing Dialysis tubing
Beaker Beaker
Water water
Time
Table 1: This is the table showing the experimental design.
The following is a set of step-by-step instructions for this experiment.
1. Cut 1 piece of dialysis tubing approximately 15 cm long.
2. Wet both pieces with tap water.
Rub one end back and forth between your thumb and fingers to open it.
Hold the tube under a faucet and let water run though it to completely open it.
3. Tie a very tight overhand knot near the end of one piece of tubing.
4. Fill the beaker 2/3’s the way full with tap water.
5. Add several drops of Iodine Solution to the beaker until the water is dark orange-brown.
6. Record the temperature of the beaker water.
7. Fill the dialysis tube with starch solution, leaving enough room to tie the open end closed.
Tie a very tight overhand knot near the open end of the piece of tube.
Rinse the tube off under the faucet to remove any starch the might be on the outside of the