Yeast Beasts in Action

Hypothesis:
If we put yeast in the acidic, neutral, and basic mixtures, the one in the neutral will allow the yeast to expand and raise the gas pressure because if the pH level is too high or too low it will not allow the yeast to react to its full potential.

Results:

When putting in the hydrogen peroxide, the measurement was approximate, and therefore there may have been less or more of the chemical, but the amount of it in all three of the test tubes was equal.

The first group of tests we did had been done incorrectly, but our mistake wasn't noticed until we already tested the first two of the tubes. Instead of only putting in two drops of the yeast solution like we were supposed to, we accidentally added 3mL, which was way too much. The following results were from the incorrect amount of yeast.

When testing the acid, the pressure skyrocketed and the solution fizzed to almost the middle of the test tube upon the addition of the Diet Coke. Once the air pressure hit 126 or so, the sensor plug actually popped off. When we reattached the plug, the pressure raised again and once it hit that 126-130 spot it popped off again. This reaction had occurred three times before we when on to the next mixture.

Next, we tested how the yeast would react to the neutral. This one had similar results to the acid, but the bubbles raised higher and we held down the top of the lid. The air pressure of the yeast and Skim Milk mixture reached about 158. It was at this point that we were considering possible mistakes that may have been made because not many other groups were having even similar results. Our group looked over the procedures again and saw that we were only supposed to put three drops of the yeast solution into the acid, neutral, or basic test tube. After discovering this, we scratched what we had already done, cleaned the materials, and got ready to start again. This next time, we only put in the 2 drops as the procedures directed.

When testing the acid there was a steady scale upward, but there was not much of a physical reaction, besides slight bubbling. The pressure started at 98 and ended at 104.5.

When we added the neutral base, the pressure slowly rose, becoming considerably higher then the other. The pressure started at 100 and ended at 105.4.

The last test, the base looked like it was going to split the acid and neutral right down the middle in the graph, but it leveled out almost right away so it ended with the lowest pressure. The pressure started at 98.81 and ended at 101.6.

This graph shows the air pressure of the yeast when added to three different substances. The red was the acid, blue neutral, and green base. In order from highest to lowest air pressures, there was the neutral, acidic and base.

Conclusion:

My hypothesis was supported by this experiment because the neutral mixture, which consisted of skim milk and Hydrogen Peroxide, gave the greatest reaction and provided the highest air pressure. It worked for the reasons that I predicted in my hypothesis, since the pH level in the acid, Diet Coke, is too high and the pH level in the base, Stomach Antacid, was too low, they did not allow the yeast to react to its full potential. Since the skim milk was neutral with its acidity level in the middle, it did let the yeast react as much as it could. One thing I learned from this experiment was how important it really is to read the directions. Luckily, since this is just an 8th grade science lab, it probably will not affect me very much in the rest of my life. But, the same principle can be applied to many, many aspects of the real world. For example, if someone were to be driving their care down the road and wasn't paying attention to the traffic lights (the "instructions") they may end up being in a car accident and could lose their life, or take the one of the other person in the accident. The entire first part of our experiment was a complete mistake, but since we redid it from the beginning, keeping the correctly made yeast solution, the actual results were not affected.

Conservation of Mass Lab Investigation

Results:

When the pop rocks were introduced to the soda, the soda began to fizz immediately, but not much more then a soda would normally fizz. The balloon began to inflate from the escaping CO2 molecules that were caught in the balloon.


Here is a picture of how much the balloon inflated with the pop ricks and soda.

The reaction with the baking soda and vinegar was a bit more easily predicted because this is a very classic science experiment that has been taught to many children when they were young. Anyhow, when the baking soda was dropped into the vinegar, the mixture started to fizz ferociously, and the large, airy bubbles reached to almost halfway up the bottle. The escaping Carbon atoms inflated the balloon considerately more then the balloon on the soda and pop rocks. After the activity subsided, we measured the amount of vinegar leftover, having exactly the same as before with 50mL. This


Here is a picture of the balloon before we added the baking soda to the vinegar.


Here is a picture of the balloon after we added the baking soda to the vinegar.


To compare the two resulting balloons, the differences are obvious. The soda and pop rocks did not reach the same amount of inflation as the vinegar and baking soda. As well, the vinegar and baking soda had more area to fill up in addition to the balloon because the bottle was mostly empty, compared to the



Conclusion:

I know the escaping molecules in the pop rocks and soda were CO2 because on the package of the pop rocks, it said that they were processed with CO2 which is also in the carbonation in soda. When the two substances met, the sugar coating on the pop rocks was melted away by the soda and left the exposed CO2. Since CO2 is a gas, it floated to the top of the bottle and inflated the balloon to make more area for the gas. If I were able to do this experiment again I would want to do it with a few different types of soda to see if that affects the results. An off-brand soda with less carbonation then a name-brand one might not bubble as much. Flavor, as well as diet or regular, may also affect the results. It would be interesting to see how the amount of carbonation compares between the different soda brands. No mistakes were made during this lab.

Chemical Reactions and Heat Investigation

The alka-seltzer in the hot water floated at the top and dissolved the fastest of the three different temperatures of water. This one was at 50 degrees C dissolved quickly within 23 seconds. The room temperature one dissolved slower then the hot water, and the tablet started to float towards the end. The alka seltzer, at 24 degrees C, dissolved in 39 seconds The third, and last, the cold dissolved overall the slowest. The alka-seltzer sunk to the bottom at first, but then started to float at the end. This one, which was only 3 degrees C took 116 seconds to dissolve, or 1:56.

This outcome was probably a result from the amount of energy being released from the water at different temperatures. When the temperature was hot, more of the water was evaporating, so the alka-seltzer responded to that by dissolving faster. This was because there was more energy that could be applied to the tablet. As the temperature lowered, there was less energy being released, so there wasn't that extra "boost" of energy to help dissolve the tablet.

Here is a graph that shows the correlation associated with temperature (aligned along the x-axis) and time taken to dissolve (aligned along the y-axis). As you can see, the higher the temperature is, the time it takes to dissolve is significantly lowers. As the temperature decreases, the amount of time it takes to dissolve increases.

Chemical Reactions Tutorial Questions

1. Reactors

2. Products

3. Chemical Change

4. rearrangement of the bonds

5. Breaking, Forming

6. Same atoms

7. Missing, New atoms

8. Rearrange the bonds

9. two, one, one, one

10. four H, four H, two O, two O

11. Law of Conservation of Mass

12. mass, atoms

13. 2Cu+ 1O2= 2CuO

14. Reactants= 1 Cu atom, 2 O atoms, Products= 1 Cu atom, 1 O atom

15. Oxygen, Oxygen

16. Oxygen, Cu, Cu

17. 2 Cu+ 1 O2= 2 CuO

18. 1 CH4 + 2 O2= 2 H2O + 1 CO2

19. 1 N2 + 3 H2 = 2 NH3

20. 2 KCI3 = 2 KCI + 3O2

21. 4AI + 3O2 = 2AI2O3

SUMMARY

1. Chemical reactions always involve creating new bonds or destroying old bonds by changing the bonding of the atoms.

2. The Law of Conservation of Mass says that the same atoms must be present before and after the reaction.

3. To balance a chemical equation, you change the coefficients of the atoms in front of each substance until there are the same number of each type of atoms in both reactants and products.

Polymer Lab Group Investigation

Results:

When we made the polymer, the result of the polymer itself was the same as the time we had made the borax polymer in class. It was a stretchy, bouncy, white, moldable polymer that felt similar to silly putty. We then divided it into four equal parts and put each one into a beaker. We then poured the different liquids that we hoped would corrode, or break down, the polymer.



The image above shows the placement of the four polymers. The one furthest to the left is the control, which was not placed in any liquid. Then there is the one that was in the acetone, lemon juice, and lastly the ethanol.

The polymers in the nail polish remover and the ethanol were almost identical in appearance. They had a very wrinkly surface that resembled two small brains.



This is the one in the Acetone (Nail Polish remover).



This is the one in the Ethanol. The surface had many wrinkles and bumps, but they are difficult to see from the picture.





The third, the one in the lemon juice, broke down so quickly that the leftover glue monomers blended with the lemon juice to make a cloudy white liquid that looked like and had the consistency of milk. When compared to the size of the other two polymers, it is obvious how distinct the difference between the size of this one and the ones in the ethanol and acetone. The one in the lemon juice broke down much more then any of the other ones and probably would have been completely gone within five more minutes.



Conclusion:

I learned that lemon juice has very corrosive behaviors. It has a pH level of only 2.3 compared to Ethanol with 7.0 and acetone with 6.5. This shows that the chemicals with lower pH levels showed to be much more corrosive. If I could redo this experiment, I would use multiple types of polymers to see if the corrosive liquids had different effects depending on what type of polymer it is. This could be beneficial in life to create substances that need to breakdown or remove polymers, such as recycling efforts, stain removers, and paint removers.


Questions:

1. What did the polymers look like after being broken down?
The polymers in the nail polish remover and the ethanol were almost identical in appearance. They had a very wrinkly surface that resembled two small brains. The third, the one in the lemon juice, broke down so quickly that the leftover glue monomers blended with the lemon juice to make a cloudy white liquid that looked like and had the consistency of milk.

2. Which corrosive material was best at breaking down the polymer?
The lemon juice definitely did the best of the 3 chemicals in breaking down the polymer.

3. Did the control test change after the 10 minutes?
No, the control stayed relatively the same throughout the 10 minutes. The only change was the slightest amount of it's moisture evaporating from the polymer, which made it slightly harder.

4. What happened when you stirred the polymer and corrosive?
The lemon juice broke down the polymer much faster when the mixture was in motion.

5. Did you make any mistakes while conducting the experiment?
No.

6. Would you like to change any of the procedures? Materials?
Yes, we did have of the amount of the borax and water because the amount that would have been made with the original amounts would have been very excessive. With this, we used the same proportions, but just to make a smaller amount to minimize waste.

7. Why do you think that alcohol is corrosive with a neutral pH?
In this experiment, the alcohol did not seem to be extremely corrosive with the polymer. I think that the reaction with the alcohal is more

8. What is acetone used for industrially? Does its applications have to due with its corrosive nature?
Acetone is the main ingredient in nail polish remover. Since nail polish is a polymer, and acetone is used to break it down and remove it, its properties are very corrosive.

Sodium Silicate Polymer Lab Investigation

Results:
You could tell there was a chemical reaction because the physical properties of the mixture changed when the ethanol and sodium silicate met. The reaction was nearly instantaneous as the film developed where the ethanol was.

Some of the similarities of this polymer and the previous one would be; they are both polymers, very moldable, and were solids. Although, the first polymer we made was much more easily moldable and soft, whereas the second was harder, more waxy and crumbly.


Here is a picture of the first polymer we made. This was the one made from the glue and borax.


Here is a picture of the second polymer we made. As you can se in the pictures, they are both very similar visually to each other.

Conclusion:
I learned that Sodium Silicate Polymers would probably not be a good material to make products out of, because it is not very durable. The product would crumble and fall apart too easily to make very many things out of it. Whereas plastics and carbon based polymers are much more sturdy, making them better to make products from. This is probably due to the bonds between the monomers in the carbon based polymers are stronger then the ones in the Sodium Silicate Polymer. One mistake that was made during this lab was that the graduated cylinder was not washed off when measuring the ethanol and sodium silicate so there was a slight residue of chalky polymer at the bottom

The Science of Addiction

Natural Reward System-
Neurons are an organism's natural communication system and are in charge of sending messages through the body through exchanging a chemical or electrical message between neurons across the body. There are many different and distinct parts of the brain, and each is responsible for one or many different possible behaviors, thoughts, actions, etc. In the middle of the brain, there is a part in which controls the mind's reward system and is in charge of controlling our feelings of motivation, reward and behavior. This part of the brain's main job is to positively reinforce behaviors that would increase survival chances. The reward pathway connects to many different parts of the brain in order to be able to sense different things that are happening within and outside of the body so that it can react to the many actions of the body. For example, if a person were very hungary and ate a sandwich, the brain would release Dopamine, the body's reward. When someone has an addiction, the reward pathway influences the body to repeat a behavior in order for the body to get the positive reward.


Drugs Alter the Brain's Reward Pathway-
Drugs change the release of Dopamine so that a large amount of it is released within seconds of the drug entering the body. When this is released the person feels an intense pleasure, often referred to as a "high". A person's brain is going to try to adapt to the new substance and therefore becomes immune to its affects. The dose of the substance is usually increased in order to still get that "high" feeling. This is often refereed to as tolerance. A person changes from a drug user to a drug addict when the act becomes so natural that it is almost a habit. Occasionally, when a dose is too much for the body to handle, an overdose , the person can even die from the dramatic changes it has on the brain and body.


Genetics is an Important Factor in Addiction-
A large part of a person's risk for developing an addiction is environmental; no one is born an addict. No single gene can cause addiction, but a combination of many genes may make a person more susceptible to develop one. Many discoveries would not be able to have been made if it were not for testing on animal subjects, mice in particular. If a gene in a mouse is identified to aid in addiction, the human counterpart can be identified by examining human DNA. On a good note, if a specific gene is found that makes a person more likely to be addicted, a medical drug could be created that would specifically target that gene and ideally make the recovery process easier.


Timing and Circumstances Influence Addiction-
If a person were to begin to take drugs when they are in their adolescence, they have a higher chance of developing a lifelong addition. During the adolescence years a person's frontal cortex is still developing, so a person is much more likely to have risk-taking behaviors that may lead to trying a drug. If a person can stay away from drugs during their risk-taking years, they have a better chance of not starting them throughout their lifetime. Social aspects can also influence a person's likelihood to do drugs. If a person is not receiving enough of the natural reward from social aspects, they will seek it some other way, which may be derived from drug use.


Challenges and Issues in Addiction-
Historically speaking, society's general negative opinion on drug use and addiction is fairly new. In the recent past, drugs were looked at as a normal part of life and were prescribed for anything from sleeplessness to weight loss. Marijuana was the third most often prescribed medication until it was banned in 1937.