Experiment and Observations I collected all my materials together; distilled water, toothpicks, clear tape, Gatorade blueberry-pomegranate, glass beaker 100 mL, colorimeter assembly – PVC pipe on foam block with cap, 9-volt battery, jumper cables – NOT IN LABPAQ (2), FDC blue dye #1 – 2 mL in pipet, 2- 12 well test strips, pipet, fine tip, multimeter – digital, 5 test tubes, wax pencil, test tube rack. First I obtained pure M and then prepared a Beer’s Law plot with the data. I then obtained the percent transmission of the various samples. Next I obtained the percent error using the theoretical and actual values. There was a 36% error and Company Q was not in compliance with the law according to their concentration values.
The data in the chart above shows that the number of drops went down by 1.25 when the liquid was changed from water to milk. Further testing may be needed. Sources of error: The main source of error in this experiment was the human error. Our group found it was difficult to keep our hands at the height of 2 cm, which is a variable that we couldn’t control nor keep track of. Also without knowing someone could bump the table, move the Petri dish or in some way caused the liquid on the penny to spill before it
Lab 5: Osmosis Purpose The purpose of this lab is to familiarize you with osmosis and, specifically, what happens to cells when they are exposed to solutions of differing tonicities. Hypothesis Since the 1% sugar solution is being placed into the same type of environment (1% sugar solution), the result should be no change in weight of the simulated cell. However, when the 1% sugar solution is placed into a 50% sugar solution environment, the cell will shrink in size because of the hypertonic tonicity; the water will rush out of the cell to create equilibrium through osmosis, resulting in the shrinkage of the cell. On the contrary, when a 50% and a 20% sugar solution are placed onto an environment of 1% sugar solution, respectively, the cells will bloat up and explode (possibly not in this experiment depending on the strength of our tubing) due to the hypotonic tonicity; the water from the 1% sugar solution will rush into the cell to create an equal amount of solute-to-solution ratio inside, and outside, of the cell. Materials & Methods Materials: · Scale · 4 6” Dialysis Tubing · 4 Transfer Pipets · Sugar · Scissors · Rubber Bands · 4 Same-Sized Coffee Cups · 250ml Graduated Cylinder · Tape Measure · Sauce Pan · 3 600ml Containers · Plastic Covering · Spoon Methods: 1.)
Physical Science Penny Lab Purpose The purpose of this lab is to see how the placement of the drops of green solution will affect how much the penny can hold up the green solution without dropping any solution on the table. Hypothesis I think that when we drop the green solution on the middle of the penny, the penny will be able to support more green solution because the green solution will have more room to spread out. Materials -25ml of mysterious green solution -Paper towel -A 150ml beaker -A penny -A pipette -A ruler Procedure 1) Place 25ml of the green mysterious solution into the beaker. 2) Squeeze the pipette in to the solution for three seconds and let go. 3) Place the penny tails up 4) Place the pipette over the letter “c” in “one cent” 5) Place the pipette 5 inches above the penny 6) Begin to slowly squeeze the solution out of the pipette, over the letter “c” while counting the numbers of drops until the solution spills out from the surface of the penny.
Gently scrape the solid from the paper using a small spatula into a 100 mL beaker. 12. Add 15 mL of sulfuric acid (1M) slowly while stirring. Observe any changes. 13.
The cap of a centrifuge tube was used to collect approximately one (1) gram of soil from the sample. This was then added to a bottle containing 99ml of sterile water for a 10-2 dilution, 1ml of 10-2 dilution was then added to a bottle containing 99ml of water for a 10-4 dilution. 1ml from the 10-4 dilution was then added to 99ml of water for a final dilution of 10-6. 1ul of each was plated on different starch agar plates with the aid of a micropipette and a plate spreader. The plates were then incubated for a week.
The number of swimming brine shrimp for Trial 4 was slightly less than that of Trial 1. This could be due to oxygen levels in the lab, or it could be due to human error in counting the numbers of eggs from the procedure, or counting the numbers of swimming brine shrimp and dead brine shrimp in analysis. Additionally, actual amounts of ethanol concentrations could have slightly varied due to human error in measuring the ethanol consistently among groups causing slightly variable viability rates. Water may also have splashed out of the dishes, contributing to a flaw in measurement. In the future, the entire study should be performed by individual groups in order to aid elimination of error.
The temperature of the water does matter in my opinion. If the water is hotter is it easier for the molecules to moves, like we seen in our beet lab from week two. If we uses say lemonade verses water I think the outcome would be completely different. I do think a person mood could affect this experiment. Reason being if someone was upset they could do something wrong by not paying attention, or if someone is angry they could be careless and put too much dye into a glass.
4. Also it helps the students to understand how yeast works and reacts to different chemicals. * Is important to shake the yeast suspension just before you add some to the test tube because all the yeast is in the bottom and you need to get it to the top to get them to the tube. * My graph shows that the amount of food and the activity of yeast were different because we put different amount of yeast. * The test tube should be set up in exactly the same way except for the differences amount of molasses because if not they would be a different result in the lab.
As salt water fish do not have access to fresh water to replace the water they are losing (due to osmosis), they have to constantly be drinking salty water in order to stay hydrated. To cope with the excess salt being held in their bodies, the kidney of the salt water fish has had to evolve, to produce very concentrated urine, and some even have other mechanisms to excrete excess salt. Because the internal structures of each fish is set up to cope with its specific environment (either salty of fresh) it is unable to adjust when placed in an unfamiliar environment. For this reason most freshwater fish can only live in fresh water and vice versa. However some fish like salmon and eels are able to cope with the changes between salt and fresh water and are thus able to survive in estuaries.