Materials Pod

2016 STEM Academy Materials Pod Overview
This pod was developed around the common interest of the study of near space effects on various materials. This group chose to investigate how near space would affect 3D printed parts, metals, rubber-bands, modeling clay, and Oobleck.

3D Printed Materials
3D printed materials are becoming more prevalent every year and with the emphasis on these materials at NASA, the materials pod wanted to investigate near space effects on 3D printed parts. In order to do this, two sets of 3D printed parts were obtained including 3D printed brains, as pictured below. One brain was sent to near space, while the other remained on earth. Additionally there were some additional pieces added to ensure there were no physical changes to the parts. Upon return, there appeared to be no obvious color change or physical differences.

Metal
According to the group's preliminary research, when metals are exposed to lower temperatures, they end up becoming brittle. Therefore it was hypothesized that if the metals were exposed to near space, then they would become brittle and crack easier. This means that it would not take as much force to crack a metal exposed to near space as it would a piece of metal that remained on earth. Therefore two distinct types of metals were obtained for study. The first was a steel constructed, zinc plated washer. The second experiment focused on different coins.

Washers
The washers were 1/8" x 1" zinc-plated fender washers. These washers were chosen since they have a large surface area while remaining fairly thin and compact. Additionally, unlike the coins, they had different modes of attachment since they were not solid discs. While some of the washers remained on earth, a few were placed inside a ziploc baggie and then sealed. Duct tape was placed on the outside of the bag and then cuts were made into the bag. The duct tape reinforced the holes that allowed for the baggie to be attached to the outside of the pod. The washers remained within the baggie during the entire flight, and were recovered with the rest of the pods. They are currently waiting to be tested against the control group. In order to do this, they will be subjected to a force with a hammer and tested to determine when deformation occurs.

Coins
While the washers were one type of metal being tested, the materials group also decided to test pennies, nickles, and dimes. Two of each type were placed into a baggie and were then secured in the same manner as the washers. However, upon recovery of the pod, they were missing. While there were no tears in the baggie, the current theory is that they slipped out through the zip tie hole. None of the coins were large when compared to the slit size and so during the violent burst, it is highly likely that the coins were ejected from their container. Therefore there was no data that could be obtained from the data.

Rubber Bands
Another material that could have some interesting results after being exposed to near space was rubber, and more specifically rubber bands. Rubber is an elastomer. This type of material is able to be stretched a great deal without suffering permanent deformation. This is apparent when working with rubber bands. They can be stretched to over double their initial length without breaking. The materials group wanted to investigate how they would behave after being exposed to near space.

Polymer Behaviors
When rubber bands are exposed to colder conditions, they actually are able to expand. Whereas in hotter conditions, they contract. This is due to the fact that there polymer structure consists of long chains. When heated, these chains want to condense or tangle, which causes the rubber to contract. Whereas, when they are cooled, the chains will elongate and relax. This in turn allows the rubber to expand. The question at hand was whether there would be any permanent changes to the rubber band's structure causing it to change its elasticity. Another question that was asked was whether or not the UV radiation would cause fatigue within the material and cause it to break under lighter loads.

Rubber Bands in Space
In order to test this, 10 rubber bands were secured to the outside of the pod and another 10 were kept on earth as a control sample. All of the rubber bands were collected after launch and are currently being analyzed. When the data has been collected, the results will be posted.

Modeling Clay
The materials group also wanted to investigate modeling clay. Therefore a small piece of air hardening modeling clay was sent to near space on the inside of the pod. Upon return, the clay seemed to be rigid as well as there were new cracks within the clay. This could have been due to the colder temperatures during the flight. Additionally, it seemed to have set up; however, there was confusion as to whether the clay was frozen or if it had set.

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. One of the interesting observations about this group's oobleck is that there was a noticeable color change. On the surface of the oobleck there was almost a yellow film where it had changed color. Current discussions about this color change are still ongoing.