Yeast Beasts in Action

WARNING! Our test was conducted without yeast in two tubes, so the outcome of the experiment might be different than expected.

Hypothesis: If we test the acid, neutral and basic substances, the acid substance's pressure will rise the fastest.

Results: We poured 3mL of hydrogen peroxide into each test tube, and used yeast for the first beaker. It was tested for 120 seconds. It was sealed with an airtight cap. We recorded the pressure (kPa) of all the tubes. It rose considerably fast (much faster than the other two). In just two short minutes, it went from 97.31 to 109 kPa, the most dynamic change of all three. Next, we poured 3mL of skim milk into another test tube, and sealed it with the cap. We tested the pressure- there was almost no change. There was only a VERY slight increase in pressure- it started at 97.32, and ended at 97.65 kPa. Our final test (tube) involved acids. We used 3mL of diet soda. It didn't rise very much, although it rose faster and higher than the skim milk. It started at 97.32, and ended at 98.88 kPa. My hypothesis was incorrect, although the pressure rose faster than the skim milk.

1. In what mixture was the activity greatest?

The activity was greatest in the tube we put yeast in. The yeast seemed to play a large role in manipulating the amount of pressure.

2. In what mixture was the activity least?

There was almost no activity in our neutral experiment (with skim milk). It had almost no change over a 2 minute period. However, had yeast been used, this could have yielded different results.

3. What can you conclude from your experiment results?

Our results were (likely) very different from others, however, as we had an absence of yeast in the last two test tubes. When there was no yeast, there were no great changes in pressure (increase, decrease). The yeast most likely affected this experiment, and we had a very different outcome.

Conservation of Mass (lab investigation)

Hypothesis: If we put the baking soda in the balloon and dump it in the soda can with vinegar, then the balloon will inflate.

Results: Our first experiment (involving the soda and pop rocks) didn't work out well. We had most of the pop rocks filled in the balloon (some fell out), and we secured it on the top of the filled soda can. We let the pop rocks go, and nothing happened. This was likely due to the fact that most of the air was escaping.

Our second (and final) experiment involved the baking soda and vinegar. This experiment actually worked, but the balloon didn't inflate very much. We poured the baking soda into the balloon, put vinegar in the cup, and dumped the baking soda in. It fizzed, and the balloon inflated slightly. It stopped halfway up.

My hypothesis was correct - to an extent. I had visioned it inflating to giant sizes, but it didn't get very far.

Chemical Reactions and Heat (lab investigation)

(all temperatures are in Fahrenheit)

HYPOTHESIS: If we add our reactants (alka-seltzer) to the water, then the reaction will change the temperature because of the ingredients in them.

RESULTS:

The room-temperature section of our experiment started exactly at 75 degrees. We recorded the temperature for 60 seconds. After 1 second, it dropped to 74.9 degrees. After 3 seconds, it went down to 74.8. At the 7 second mark, it went to 74.7. At 10 seconds, it dropped to 74.6. At 16 seconds, it went down to 74.5. At the 28 second mark, it went down to 74.4 degrees, 74.3 degrees at 40 sec. and stopped at 74.2 at the end of the minute.

We then performed the "cold" test. We put an ice cube in the cup and stirred for about 60 seconds. When we started recording for one minute (again), it quickly dropped from 77 degrees to about 50 in a matter of 10 seconds. It slowly sunk to 49.1 degrees after we put in an alka seltzer.

The last test we did was the hot plate test. We recorded the water on a hot plate for about 75 seconds (or until it rose to 122 degrees). Then, we took it off the plate, turned it off, and put in an alka seltzer. It gained 30 degrees in the time it took to add the seltzer again, so it stopped at about 142 degrees.

To sum it up, our reactants actually did very little to influence the temperature of the cold, hot, and regular water. There was never a change greater than two to three degrees.

ChemThink Chemical Reactions

1. Reactants.

2. Products.

3. Chemical change.

4. Rearrangement of bonds.

5. Breaking, or forming.

6. Atoms.

7. Missing or new.

8. Rearrange the bonds.

9. 2, 2, 1, 1.

10. 2, 1, 2.

11. Law of Conservation of Mass.

12. Cu and O atoms.

13. 2 Cu + 02 = 2 CuO.

14. Reactants: 1 Cu, 2 O- products: 2 Cu, 2 O.

15. CuO.

16. Cu, O2.

17. 2 Cu + 02 = 2CuO.

18. 1CH4 + 2O2 + 2H20+ 1CO2.

19. 1N2+ 3H2 = 2NH3.

20. 2KClO3 = 2KCl + 3O2.

21. 4Al + 3O2 = 2Al2O3.

1. Reactants and products.

2. Present before and after the reaction.

3. Coefficients, atom.

Polymer Lab Group Investigation

Problem: How will more glue affect this experiment?

Hypothesis: If we use 2x more glue and 2x more borax solution, then the polymer will stretch farther because it has more contents.

Results: After making it into a solid, we stretched the new polymer. Our polymer stretched out twice as much (on average). During our first experiment, the polymer barely made it to 15cm. It was stretched twice horizontally and twice vertically. The two horizontal tests turned out to be 32cm and 28cm, and the two vertical tests were 25cm and 30cm. It stretched about 2.5cm more horizontally. After this, Derek bounced the polymer two times after forming it into a ball. The first test was 2cm. Derek waited five minutes and tested it again- it bounced about 4cm. I believe it bounced/stretched higher/further because the polymer was significantly larger- we used 80mL of glue and 50mL of borax solution. Because of this, it was slightly harder to form.

The Science of Addiction

The brain is divided into different regions that are responsible for performing specific functions. In the center of the brain sits the reward pathway. The job of the reward pathway is to make us feel good when we engage in behaviors that are necessary for survival.

Neurons are the cells responsible for passing chemical and electrical signals along the pathways of the brain. Information flows from one neuron to another across a small gap called a synapse.

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Within seconds of entering the body, drugs cause dramatic changes to synapses in the brain. Drugs can cause a jolt of intense pleasure. Drugs of abuse affect the brain in such a dramatic way that it must try to adapt. The faster a drug is delivered to the brain, the more likely it is to be addicting. An overly large dose can kill the user.

PET scans can help show the effects of drugs on people. As the brain continues to adapt to the presence of the drug, regions outside of the reward pathway are also affected. They become "hard-wired." Once this happens, drug-seeking behavior becomes driven by habit, almost reflex. This is how one becomes a drug addict.