SECTION ONE: Methods
Lab 1 – Diffusion and Osmosis can be broken down into four parts (A, B, C, and D). Lab 1A – Diffusion
In this exercise, we tested diffusion through dialysis tubing. This was done through a demo with the teacher, rather than individually in groups. First, a piece of 2.5cm dialysis tubing was obtained. Then one end was folded and clipped securely so that a solution poured into the bag would not leak out. Next, the other side of the bag was opened. For step two, a 15% glucose/1% starch solution was tested for the presence of glucose with Benedict’s, and we recorded the data in a table. Using more 15% glucose/1% starch solution, 15 mL was placed in the dialysis bag. The other end was tied, leaving room for the contents in the bag to expand. The color of the contents was recorded. This solution was then tested with Benedicts and the color was once again recorded. A beaker was filled with enough distilled water to submerge the bag, and it was tested with Lugol’s for starch. This was then tested also for glucose. The bag was then immersed in this beaker of solution. This was left to sit for around 10 minutes, after which it was heated up. The final color was recorded. Then the liquid in the beaker was also tested for glucose and the color was recorded. As opposed the lab manual, the demo done included an extra step in which the bag was heated. Also, a clip was used to keep the tubing from releasing solution out of the ends rather than string. Lab 1B – Osmosis
Lab 1B required six different dialysis tubes that would be filled with varying sucrose solutions. However, due to time constraints, the lab procedure was modified. Instead, every group did two sucrose solutions and a class data chart was made to pool the findings. For our group, 0.4M and 0.6M sucrose solutions were tested.
First, we obtained two 10-cm strips of dialysis tubing. For each tube, we folded up the bottom end and tied it securely so that...