Starches are found in potatoes, a type of plant that contains carbohydrates. The topic is important because it shows how starch can change over time:)
Does starch or iodine travel through a semi-permeable membrane (dialysis tubing)?
If iodine travels through a semi-permeable membrane, then it will dissolve into the starch.
- Soak dialysis tubing in water for approximately 2 minutes.
- Open dialysis tubing by placing between fingers and moving fingers back-and-forth.
- Tie dialysis tube by twisting, folding and using piece of string approximately 2 cm from edge.
- Add 8mL of starch solution to dialysis tube.
- Seal second end of dialysis tube by repeating Step 3.
- Rinse dialysis tube well with water and dry gently.
- Fill 250mL beaker with 200ml of water.
- Add drops of idoine until the soluiton is “tea” color, approximately 20 drops.
- Place dialysis tube in the beaker and let sit for 20 minutes.
- Record observations every 5 minutes.
I think that the starch will start to bubble up.
If iodine travels through a semi-permeable membrane, then it will dissolve into the starch. My hypothesis was correct. Starch and iodine does not travel through a semi-permiable membrane. The color from the starch did not leake through dialysis tube, there was no colored water, it was clear. It took 4 days for the changes to occur in the beaker. A way to improve this experiment is to tie the ends of the dialysis bag tighter.
|Quantitative (#)observasions|| filled beaker with 250
ml of water
|used 20 drops of iodine|
|Qualatative(words) Observations||took 4 days for changes to occur||the liquid in the daysis tube turned dark purple|