Investigation Pod

2016 STEM Academy Investigation Pod Overview
This pod was a combination of different materials and processes that students wanted to investigate. They evaluated the effects of near space on glow sticks, construction paper, yeast, and Oobleck. In order to analyze these effects, a series of on-the-ground experiments and background research was conducted in order to gain a better understanding of the phenomena.

Glow Sticks


Glow sticks provide great party favors and are typically regarded as a child's toy; however, they actually are a contained chemical reaction and can be used for science. Within glow sticks there are two different solutions that are housed within two distinct regions. The first is a diphenyl oxalate compound. In order to produce different colors, there are dyes also present within this solution. The second solution is housed in a smaller, distinct cylinder within the glow stick and is filled with hydrogen peroxide. In order to activate the glow stick, typically the glow stick is bent until there is a crack sound. The glow stick is then shaken and the glow effect is triggered. What is happening during the activation phase is that the second smaller container is being broken since it is typically made of glass.This allows the hydrogen peroxide to mix with the diphenyl oxalate compound, and a chemical reaction then takes place. During this reaction, the excess energy is lost as photons of flight. These are simply excited electrons, and this process is known as chemiluminescence.

Correlation Between the Temperature and Intensity of the Glow
Since glow sticks are just a chemical reaction, the correlation between the intensity of the glow and the ambient temperature was of interest. Four glow sticks, three pink and one blue, were obtained, activated, and placed in approximately 120° F water. The initial intensity was recorded as a qualitative measurement. At the same time, two additional glow sticks, one pink and one yellow, were activated and then placed into a bowl with ice. The initial intensity was also recorded. Since these two experiments were run side by side, the intensities could be compared in real time. Through the use of ice and hot water, the ambient temperature for the glow stick could be manipulated to examine the possible correlation between the temperature and intensity. The water needed to be replaced during the experiment in order to maintain the warm environment for the first set of glow sticks. During the experiment, it was observed that the glow sticks in the ice were duller than those in the ice bath. Additionally, the frozen glow sticks lasted longer than those in the hot water. This makes sense based on the preliminary research. Glow sticks are simply a chemical reaction and so a warmer temperature will cause the reaction to become accelerated. Conversely, a colder temperature will slow the reaction, allowing the glow sticks to last longer.

Glow Sticks in Near Space
In order to prepare for the launch, 12 glow sticks were obtained. There were six pink glow sticks and six yellow glow sticks. They were then sorted into groups so that there was a set of three yellow glow sticks that were cracked and another set of three that were un-cracked. The reason why there were un-cracked glow sticks was to investigate whether the burst would have a great enough force to break the cylinder containing the hydrogen peroxide, and activate the glow stick. Within the sets of three glow sticks, one would be attached to the outside of the pod, one would be attached to the inside of the pod, and one would remain on the ground as a control glow stick. These groupings were then replicated among the pink glow sticks. Every glow stick had a marking on the outside for whether or not they were supposed to cracked, as well as where on the pod they were located. This allowed for an easier analysis later and prevented any confusion between glow sticks later. The glow sticks were attached to the pod using zip ties.

All of the glow sticks survived the flight and remained attached to the pod. Upon initial inspection, a color change was apparent in the yellow glow sticks. The yellow un-cracked glow stick that was attached to the outside of the pod had become a light orange. The yellow, un-cracked glow stick that was on the interior pod did not have this color change. Rather, it remained the initial yellow color. The cracked yellow glow sticks had this same trend except it was not as blatant of color change. The pink glow sticks however did not experience a color change in either the cracked or un-cracked. The current working hypothesis is that the yellow dye solution reacted with the UV light, causing a color change. This would make sense since there was a greater color change in the un-cracked glow sticks. The cracked glow sticks had already began their chemical reaction, whereas the un-cracked glow sticks had the pure diphenyl oxalate compound with the dye. However, the pink dye solution was unable to experience this reaction, so it must be something to due with that particular dye. In order to be able to have a more definite answer, research must be done to understand the interaction between dye solutions and UV light.

It is also worth noting that none of the un-cracked glow sticks were activated during the flight. While the balloon burst is violent and can produce accelerations eight times greater than the standard calibrated gravitational acceleration, it is unable to activate the glow stick. The issue is that in order to activate the glow stick, a force must be applied at the ends of the glow stick, forcing the middle to experience a large deflection, therefore breaking the glass container. The force experienced during the burst may cause the glow stick to shake violently but it will not crack the center glass container.

Construction Paper
When some materials are left in the sun for a long duration of time, they fade and loose their initial color. In order to investigate this, the question of whether or not materials would fade in near space due to the UV rays was posed. Since the balloon would allow the pods to be exposed to UV light for only a small fraction of time, a material was needed that has a tendency to fade quickly. Due to personal experience, construction paper was decided to be the testing material. It has a tendency to fade quickly with sun exposure as well as time. However, since this has been a known manufacturing weakness, companies now produce acid–free construction paper. This is supposed to hinder fading and allow for greater construction paper longevity. While this could possibly decelerate fading, construction paper would still be used to test if this new formula would prevent against fading.

Four small panels were then placed to the top of the investigation pod. These panels were each decorated with different patterns composed of different materials. This was to see if there were any interactions between the materials and the construction paper. The paper was attached with duct tape. This was done so that the duct tape could then be removed and the paper could be checked to see if the shielded portion was a different color than the bare construction paper. In addition to these squares, other squares of just black construction were attached to the pod. These also implemented the duct tape attachment method.

Yeast


Yeast is a single-celled member of the fungus family and is actually alive. If water, yeast, and sugar are mixed together, then the organism will release carbon dioxide. This is what will make bread nice and fluffy. In order to investigate this phenomenon, students hooked up an apparatus that allows for the carbon dioxide to be emitted directly into an indicator solution. The investigation is shown in the photographs.

Production of Carbon Dioxide
In order to contain the materials, a pop bottle was obtained and a small hole was made into the top of the lid. This allowed for clear vinyl tubing to be inserted after the yeast, sugar and warm water were mixed. This tube was run to a bowl containing cabbage water. Cabbage water is a natural indicator solution. If a solution is basic, then it will turn a dark blue color. If the solution is acidic, then it turns a light pink/purple color. In order to ensure that all of the carbon dioxide was going to the indicator solution, the top of the bottle was sealed with modeling clay. This mixture was left alone for approximately 30 minutes. The photos are able to show the change in color since the indicator solution started off a deep blue/purple color and then became a light pink/purple solution. This meant that the carbon dioxide produced by the yeast made the solution acidic. The carbon dioxide reacts with the water in the indicator solution and forms carbonic acid. This is why the indicator solution changed color since the solution became acidic.

Yeast in Near Space
However, students wanted to learn more about whether the yeast would behave differently after being exposed to near space. The sugar and yeast combination was placed within Ziploc Baggies and attached to the inside and outside of the pods with zip ties.



The yeast was able to withstand the flight. Upon recovery, the yeast and sugar were looked at under a microscope. While there were no significant changes within the yeast, there were significant changes between the sugar samples. The sugar that was on the inside of the pod had a perfect crystalline structure. However, the sugar that was attached to the outside of the pod was sheared. Instead of the expected crystalline structure, the sugar almost looked like jagged river rocks. There were different erosion rates with the sugar, which was not the initial question, but was an interesting finding. The control sugar also had the same crystalline sugar as that on the inside of the pod.

Oobleck
The final area of investigation for this pod dealt with the substance commonly known as “Oobleck”. While this is not a living thing, many students were passionate about this non-Newtonian fluid and so almost every group was able to conduct their own tests.

Non-Newtonian Fluids
A non-Newtonian fluid is able to change its viscosity or flow under different circumstances. Sometimes the rate at which it flow depends on the applied stress and can also be dependent upon time. In Newtonian liquids, they have a constant flow or viscosity. The fluid’s flow will change depending on pressure or temperature. However, with non-Newtonian fluids, the amount of force applied can cause the liquid to behave differently. Oobleck is a great example of a non-Newtonian fluid. It is able to behave like a solid under certain conditions, and like a traditional Newtonian liquid in other circumstances.

How to Make Oobleck
Making Oobleck is simple. The only ingredients are cornstarch and water. Water is added to cornstarch until the mix will flow very slowly. Once they are mixed, experimentation can proceed. The students discovered that if you simply hole a chunk of Oobleck in your hands, then it becomes runny and will drain off of your hand. However, if you try to punch a bowl of Oobleck it behaves as a solid and will resist deformation. If the Oobleck is rolled, then you are able to roll it into a nice ball. However, the moment that you stop rolling, the Oobleck simply melts away and becomes runny.

Oobleck in Near Space
Once the baseline Oobleck consistency was obtained and experimented with, the Oobleck was divided into small containers and the tops were duct taped shut to ensure that Oobleck would not leak onto the interior of the pods. Then these containers were secured to the inside of the pod and ready to launch.

After the flight, the Oobleck was retrieved and the students noted that it was acting as a solid. However, this is most likely due to the fact that it was simply frozen. As the time progressed, the Oobleck began to melt and the consistency was eventually the same as the control sample that was never exposed to near space.