Wednesday, September 24, 2008

Density Lab Report

Jennifer Wilson
9/24/08

Chemistry 201-2

Mr. Schoudel


Introduction:
In science there are several questions that require experiments and tests to discover and understand the result. Our class recently discussed density, mass, and volume. All three of these components were key in solving our scientific question. Our experiment was to find the most accurate way for a vial to float into two different types of water, with different densities. The two types of waters consisted of warm fresh water and cold salt water. The water was poured into a fish tank, with blue die in the warm fresh water, displaying the two layers of water. We were given the information that the density of the warm fresh water was greater than 1.00 g/cm3 and the density of the bottom layer was less than 1.00 g/cm3. When my partner, Lucy and I first heard about this experiment, we did not know how to approach it. We went through a long process of brainstorming ideas about how to find an accurate way to approach this question. Our first thoughts were to put some type of weight in the vial to allow it to sink when placed in the water. We thought that putting boiling water or freezing water in the vial, would add weight to the vial, causing it to sink. We were not sure if this was at all accurate, which is why this experiment was so challenging for us.

In addition, it was almost like trial and error, until we observed our materials and the question, which lead us to a more accurate procedure. We were correct about putting weight in the vial, however water was maybe not the most accurate object to add weight with. We also observed the density formula; Density = Mass/Volume. This gave us the idea that we could find the density of the vial, and as a result the vial would float in the middle of the two waters. Our goal was to make the mass of the vial the same as the volume. This helped our process to become more accurate and answered several of our questions.

Hypothesis:

Our hypothesis is to place a type of weight in the vial; therefore the vial will float in the middle of the two types of water. Our initial weight was more water, however as the lab progressed, we decided that we would try to add a different weight, such as sand or table salt.

Materials:

• One large fish tank
• One small plastic vial
• Warm fresh water
• Cold salt water
• Sand
• Density Formula: Density → Mass/Volume
• Small (most accurate) graduated cylinder
• Analytical scale
• Pencil and pen to record data and results

Methods:

• Record initial mass of the vial
• Put water in graduated cylinder to determine volume (fill to 60 ml mark)
• Put water in vial (Fill to the top)
• Test the volume of the vial
• Record the mass of the vial with sand
• Test the experiment
• If it does not succeed, then keep adding or subtracting weight from the vial
• Also continue to test the weight of the vial each time, therefore your result is more accurate


Data/Results:

Test # 1 X

Total Mass: 24 grams + weight of vial = approx. 28- 30 grams

Result:
Sunk to the bottom of the tank

Test # 2 X
Total Mass: 29. 457 grams
Result
: Sunk to the bottom of the tank
Test # 3 X
Total Mass:
22.2 grams
Result:
Float/ Remained a little above water
Test # 4 X
Total Mass: 24.28 grams
Result: The vial remained at the top of the water
Test # 5 +
Total Mass: 25.2 grams
Result: The vial remained in the middle of the two waters


Discussion/ Analysis:

Our hypothesis for this experiment was to put some type of weight in the vial; therefore the vial could float in the middle of the two types of water. This was a step in the right direction because it was important to add more weight to the vial, to successfully carry out the experiment. As the experiment progressed we noticed that adding sand to the vial would add weight and therefore would make our experiment accurate. We had a lot of difficulty discovering the correct amount of sand because we had to observe the density formula as we were adding or subtracting weight from the vial. The volume of our vial was 24 ml and we had to make the mass 24 as well because we need to balance out the density, which was 1 ml. This does not seem very difficult, however you had to remember that the vial also weighed something; therefore we had to consider this and adjust our experiment to this weight. Furthermore, each attempt to sink the vial low enough to float in the middle, was closer and closer. With out first attempt, we forgot to subtract the weight of vial, therefore making the vial too heavy and sinking right down to the bottom. On our next tries we either added to much sand or subtracted too much sand, making this a very repetitive process. Although this was quite repetitive, it made us observe every step of our experiment to make sure it was the most accurate we could make it.

In addition, one thing that could have made our experiment more accurate was taking our time with each step. I think the reason we had so many attempts was because we sometimes were so anxious and excited about testing the vial, we would remove too much weight, add too much, etc. These were key elements in having a successful experiment. Although we rushed our experiment as it became more exciting and interesting, we enjoyed each step of the process.


Conclusion:

The vial lab was a fun and interesting way to introduce the density formula. This lab was not very obvious; therefore it took all the groups time to create a valid hypothesis and experiment. My partner and I struggled in the beginning of the lab because we were both unsure at how to approach the lab. However, as we looked at our materials and information, we were able to unfold the key points that were essential to a successful experiment. Even given the density formula, it was still not an easy task. Furthermore, this lab was very frustrating, as we became closer and closer to our final answer. Each step was so close, yet so far. We either needed to at more weight or subtract weight; it was not a simple job. In addition, we were also very nervous with each step because we were sometimes unsure of the result. Finally, this was an interesting and challenging experiment, however we learned to take our time and try to be as accurate as possible.

Tuesday, September 16, 2008

Lollipop Lab Report

Jennifer Wilson
Chemistry 201-2

Mr. Schoudel


Introduction:

The scientific method is a key process when solving a problem in science. Questions, hypotheses, experiments, observations, gathering and analyzing data, and drawing a conclusion are all important steps in completing the scientific method. Our class has discussed this method and decided to construct an experiment that would follow the steps we outlined in the scientific method. The purpose of the lollipop experiment was to try to discover how many licks it takes to reach the tootsie filling of a tootsie pop. Our hypothesis was from Mr. Owl’s tootsie commercial, which stated that it takes exactly three licks to reach the chocolate filling of a tootsie pop. We found that there were many different variables that contributed to our experiment, such as the size of tongue, pressure of tongue when licking the lollipop, how one lick’s a lollipop, etc. There are many variables as well as limitations and restrictions that one must compromise with when testing a scientific question. As a class we did have some restrictions, such as time limit, space, and equipment. It was essential that we compromise and come up with an experiment that fit into the limitations of space and resources.



Hypothesis:

Our hypothesis was from Mr. Owl's tootsie commercial, which stated that it takes exactly three licks to reach the chocolate filling of a tootsie pop.


Materials:

• One tootsie pop for each student (15 lollipops)

• Multiple Glasses/Cups of water

• Students from each class (15)

• Stop watch to record time

• Pencil or pencil to record the data and results

• Controlled environment


Methods:

• Remove lollipop wrapper

• Take a sip of water (not a large gulp, but around 1 tablespoon of water)

• Lick the lollipop on one side for the entire time it takes to reach the chocolate center

• Count how many licks you take in three minutes

• Every three minutes take a sip of water

• Repeat steps 2 & 3 until you reach the chocolate filling of the tootsie pop

Data/Results:
Average Licks: 267.7
Median: 256
Mode: 312

Average of Mean, Median, & Mode: 278
Jennifer’s Results

Total # of licks: 261
Total Time: 8:30 Minutes


Discussion/ Analysis:

Our hypothesis for the lollipop lab was that it would take three licks to reach the chocolate filling of a tootsie pop. This is a false statement and is rarely every true due to the number of variables that are put into account. We discovered that it takes almost ninety times more licks to reach the center rather than three simple licks. Our entire class decided on taking sips of water every three minutes to keep our mouths moist, therefore making our experiment as consistent and accurate as possible. As a class we also decided to lick only one side of the lollipop and when that specific side displayed the chocolate filling, we had reached the center. We had a large debate about whether or not this was the more accurate lick. Many students said to put the entire lollipop in our mouth, while others said to just lick one side and keep it consistent.
To make our experiment more accurate, we could have put the entire lollipop in our mouths, which would represent the licks it took around the entire lollipop. Furthermore, we only took sips of water every three minutes. Our original time was five minutes, but we soon discovered that our mouth gets very dry and it is important to take a sip of water more frequently, to have an accurate experiment. There are also many variables to consider, such as the pressure one hits the lollipop, the type of lick, etc. If half of the class licked the lollipop on one side and the other lick the entire thing, but still keep the time consistent, we might have arrived at different averages. The main procedure that we would need to improve on is the type of lick and the speed at which you lick the lollipop.

Conclusion:

The lollipop experiment was a great way to begin the lesson on the scientific method. We were instructed to create a hypothesis, test our hypothesis, provide observations, gather and analyze date, and draw a conclusion. Although our hypothesis was incorrect we were able to identify several variables that had an affect on our experiment. In addition, we learned to compromise with our limitations and restrictions. In many situations there are always limitations and it is essential to compromise to carry out a successful experiment. During our experiment we noticed that students were reaching the center of the lollipop faster than others, which shows the pressure at which some licked the lollipop and the speed at which they licked. In an experiment like this, is it extremely difficult to come up with a perfect tester (in our conditions), which is why there were many variables to consider. Although we did not have many resources for this experiment, we had a lot of fun learning and working the scientific method.