Plastic Tubing

Decent Essays
Fill the plastic tub (or bucket) about one-third full with water. Fill the graduated cylinder with water. Remove all air Attach the cylinder to the side of the tub with packing tape. Next, create a way to bring the CO2 from the yeast to the gas collection system. Make a hole in the bottle cap, just big enough to insert the plastic tubing. Use a drill or a nail and a hammer. Insert a piece of plastic tubing through the hole so that it sticks out about 1 inch and should remain above the surface of the yeast solution. Seal the tube to the cap with epoxy or silicone sealant so that it is air-tight. Allow it to dry. Label one bottle "air" and the other "no air". Test the yeast with a solution that has oxygen. Boil 3 cups of water and let the water…show more content…
If you let it become completely filled, and the next condition you test makes even more CO2, this could lead to poor and inaccurate results because the graduated cylinder may fill up before the test time is over. Tip: If the solution makes a large amount of CO2 very quickly, you can try to make it produce less CO2 by using less sugar and possibly less yeast. For example, you could repeat this step using 1 tsp. sugar (instead of 2 Tbsp.) and 1 or 2 tsp. yeast (instead of 2 tsp.). When the time is up, note how much CO2 was collected. Record the results in the data table in the lab notebook Repeat steps 1 and 2 to re-fill the gas collection cylinder and reset the gas collection system. Carefully rinse out the yeast solution from the bottle. Repeat steps 4 and 5 at least two more times. Run at least three separate trials for each condition. Repeat steps 4–6 but this time test the solution without oxygen by making the following changes: Skip step 4c so that you do not aerate the solution. Boiling the water should have minimized the dissolved oxygen in the water. In step 4e, pour the solution into the "+air" bottle and cap it, placing the open end of the collection tube inside the gas collecting
Get Access