Experiments
Table of Contents
Radiation Effects of Various Materials on Temperature
by Jeremiah Bush
1) ABSTRACT
The types of materials used in super-atmospheric vehicles have heavy influence on how radiation is absorbed and consequently the temperature of that vehicle. The difference in temperatures between employed materials can be attributed to the reflectivity and absorption of thermal radiation. Previous research has relied on data from lab controlled environments, extensive testing in the harsh realities of the upper atmosphere presents an opportunity to confirm a known phenomenon. We use data from three temperature sensors and an altimeter to decompose a correlation between temperature and altitude. These data points can be correlated further with known thermal radiation values at altitude to determine the effect of different materials on temperature. Our findings further support the known phenomenon of metal’s ability to reflect incoming thermal radiation. The data indicates that cellophane, in contrast, absorbs thermal radiation and has an on average higher temperature.
2) INTRODUCTION
Superatmospheric vehicles are incredibly complicated and dangerous, with many environmental factors attempting to take control over normal operations. The harsh environment that surrounds a vehicle of this nature must be controlled and or limited in effect for the continuous operation in future endeavors in orbit or even distant planets. A harsh product of the environment is temperature which can affect the internal workings of superatmospheric vehicles. Temperatures in these vehicles are caused by radiation, which can be heavily curtailed by the usage of specialised materials. Currently, metals are known as one of the most excellent sources for reflecting inbound radiation and thereforth reducing temperatures. Testing three material states on a high altitude balloon will allow for a correlation to be made that reaffirms aluminum foil as a superior heat blocking source in superatmospheric applications. As the altitude of the payload increases past the ozone layer the temperature of the aluminum wrapped sensor will be the lowest due to the high reflectivity of metals on thermal radiation. The cellophane wrapped sensor will be the highest temperature of the three as it absorbs thermal radiation and keeps it within the space between the cellophane and sensor itself. The uncovered temperature sensor will be a moderate temperature between the cellophane and tinfoil as it will not store absorbed heat as much nor reflect as much thermal radiation.
3) METHODS
Three DS18B20 sensors were taped onto a triangular wooden base. These three temperature sensors were connected to an arduino which acted as a buffer between the sensors and the Raspberry Pi zero. One sensor was wrapped in generic aluminum foil, another one in cellophane. The third sensor was left uncovered to be the control of the group. The arduino was programmed to put the extracted temperature sensor data into a readable format for the raspberry pi. The data was then organized into columns and uploaded on a microsd card. Helium was filled in a balloon attached to the payload until an upward force of 5 Newtons was applied. The balloon was released and recovered one day later.
4) RESULTS
The three temperature sensor’s data was decomposed into usable points on a graph. As shown in the Temperature vs. Altitude graph the temperatures in order of highest to lowest were: Cellophane, Uncovered, Aluminum Foil. The temperature fell until the balloon entered the ozone layer at 14,000 meters. After entering the ozone layer the temperature rose until the balloon’s max altitude 33,340 meters and a temperature of 3 degrees Celsius.
5) DISCUSSION
Our retrieved data supports that the Tin foil wrapped temperature sensor was colder than the other two temperature sensors. According to data analysis of figure 1-1 using logger pro software the foil wrapped sensor was on average 7 degrees Celsius lower than the baseline uncovered temperature sensor. This supports what Dr. Christopher S. Baird says in relation to metal’s ability to reflect incoming thermal radiation, “The key property that distinguishes a metal is the presence of a large number of electrons that are effectively free to move around. Since the conduction electrons in metals are free to move about, they are able to quickly and easily respond to the waving electromagnetic fields present in thermal radiation. This strong response leads to a strong reflection of the thermal radiation.” (Baird). The cellophane covered temperature sensor was a polar opposite of the tin foil sensor, because there was no metal for reflection, UV rays were able to be absorbed and a larger magnitude of heat was produced. The ozone layer protects mainly against UV rays which are on the spectrum of thermal radiation, “Thermal radiation is electromagnetic radiation emitted from all matter that is at a non-zero temperature in the wavelength range from 0.1 micrometers to 100 micrometers. It includes part of the ultraviolet (UV), and all of the visible and infrared (IR).” (Jose Meseguer). The average temperature of the cellophane wrapped sensor was 2 degrees Celsius above that of the uncovered sensor according to a data analysis of figure 1-1. The integrity of our temperature data is confirmed by figure 1-2 by researcher Nick Strobel. The temperature properly begins to start rising in magnitude around 14 to 15 kilometers as the ozone layer is entered and more radiation can reach the three sensors.
6) CONCLUSION
Metal’s unique properties confirm it as one of the best materials to use in superatmospheric vehicles when the need to control heat is relevant. Similarly, materials that have no reflection of thermal radiation such as cellophane could be used to increase the heat of a system. On average the tinfoil wrapped cellophane sensor was 8 degrees Celsius below the baseline temperature while the cellophane wrapped temperature sensor was 2 degrees Celsius above.
Effects of Ozone Concentration on Temperature
by Jeremiah Bush
1) ABSTRACT
Ozone concentration has a drastic effect on the amount of radiation absorbed and consequently the amount that reaches the surface of earth. The difference in ozone concentration between altitude will affect the amount of radiation hitting an object, and thereforth the temperature of that object. The current explanation for this trend are ozone molecules progressing into a more stable oxygen state and absorbing the harmful radiation. The ozone layer is not uniform in concentration composition, this presents an opportunity for us to reconfirm a commonly known phenomenon and determine the ozone concentration at different altitudes in our local environment. We use data from an altimeter, temperature sensor, and UVA sensors to correlate temperature with altitude and the UVA magnitudes at those specific altitudes. Although our UVA sensor yielded unusable results, a good correlation between temperature and altitude was made confirming prior research into the atmosphere and the ozone layer. As the altitude increases within the stratosphere an increase in temperature and UV radiation magnitude will be shown.
2) INTRODUCTION
Radiation emitted by the sun and other sources are extremely harmful to the human body, without protection severe damage would be sustained. The main source of protection against this detrimental radiation is the ozone layer. The ozone layer starts at the beginning of the stratosphere and gradually decreases in concentration until the mesosphere in which radiation is free to traverse. The ozone is not uniform in composition and differs in concentration depending on location and season. Currently, ozone concentration is determined by mass launches of disposable weather balloons using sensitive UV detecting sensors. The opportunity to create a balloon such as the ones launched and be able to retrieve it for our own purposes presents a unique team building and learning experience. The main limitations of our experiment consist of consumer grade sensors, ones not sensitive enough to detect the intricate changes of ozone concentration throughout the layer. Despite this limitation, a credible estimate can be made on where the ozone layer begins and ends by data analysis of the correlation between temperature, altitude, and UVA. As various compounds and chemicals are released into the atmosphere it can affect the ozone layer in unforeseen ways. By repeatedly monitoring it a conducive conclusion can be formed on the health of our ozone layer and future way of life.
3) METHODS
An altimeter and temperature sensor were integrated in a pre built flight computer. This flight computer was bolted on one of the sides of a triangular wooden base. A UVA/UVB sensor was taped on one of the sides of the triangular base. The flight computer was setup to directly output it’s data into a spreadsheet on a microsd card. The UVA/UVB sensor was wired to an arduino which was then wired to a raspberry pi. The arduino served as a formatting device for the data which transferred it into the raspberry pi which put the data into a spreadsheet. The data was then organized into columns and uploaded on a microsd card. Helium was filled in a balloon attached to the payload until an upward force of 5 Newtons was applied. The balloon was released and recovered one day later.
4) RESULTS
The altimeter, temperature sensor, and UVA/UVB sensor’s data was correlated against each other. The UVA/UVB sensor’s data unfortunately did not yield any usable results. The altimeter and temperature data was correlated. The temperature fell until the balloon entered the ozone layer at 14,000 meters. After entering the ozone layer the temperature rose until the balloon’s maximum altitude of 33,340 meters and a temperature of 3 degrees Celsius was reached.
5) DISCUSSION
Unfortunately our UVA/UVB sensor yielded unfit data for use in this experiment. We believe there may have been a coding issue along with some settings that were not tweaked correctly to cause this. However, our altimeter and temperature data is still intact. Our correlation between temperature and altitude is shown in figure 1-2. This data supports prior research about how the atmosphere is constituted, with the ozone layer being clearly visible past the minimum of the figure 1-2 graph at around 14,000 meters. This data is confirmed by former researcher Nick Strobel and his diagram of the atmosphere. After the payload entered the stratosphere, the ozone concentration gradually degraded and more UV radiation was allowed to impact the balloon. This is indicated by a rise in temperature past the 14,000 meter mark. This reasoning is further supported by Figure 1-3 by NASA as it shows the decrease in ozone concentration as the altitude increases throughout the stratosphere and then increases again. Our payload reached an altitude of 30,000 meters, if it progressed to a higher altitude it can be reasoned through the figure that the temperature would decrease again to 0 Kelvin or -273 degrees Celsius, absolute zero in temperature.
6) CONCLUSION
The increase in temperature as the balloon traversed the ozone layer confirms the radiation blocking characteristics. Although we had technical difficulties with our UV sensor, a credible and conducive conclusion could be made correlating our data with that done by other researchers. As the altitude increased beginning in the stratosphere, the temperature can be seen to increase with the according decrease in ozone concentration.
Marshmallow experiment
by Marta Laatsch
1) Abstract
This experiment was intended to measure the effects of dramatic changes in air pressure on porous, flexible substances such as marshmallows. We hypothesized that a mini marshmallow with dimensions ≈1cm*1cm*1cm at nearly 1 atm of pressure and a temperature of 35°C would increase in dimensions by 350% when brought to 30000 m in elevation.
2) Introduction
Typical marshmallows are made of sugar, cornstarch, modified corn syrup, gelatin, and air. In marshmallows, gelatin acts as an emulsifier, which allows the marshmallow to hold its shape. When in the stage of the marshmallow making process after the sweeteners are boiled, gelatin is added, and the mixture is strained and whipped. When whipping the mixture, it turns foamy and doubles or even triples in size due to the air added in this process. Therefore, a significant percentage of the volume of a marshmallow, ~50-65%, is air. The air is made of ~78% nitrogen and ~21% oxygen.
Air pressure is measured in atmospheres (atm). One atm is equal to the average air pressure at sea level, ~101325 Pa, or ~14.7lb/in2. As elevation increases, air pressure decreases. Raider 1 measured both air pressure in Pa and elevation in meters, allowing us to measure the relationship between these two factors. When an air-filled substance previously in equilibrium with the surrounding air pressure is exposed to a lower air pressure, the substance should expand due to the increase in the relative pressure on the inside pushing out against the boundaries of the substance. The air pressure necessary to cause this change depends on the strength of the substance.
3) Methods
We obtained a marshmallow and placed it in the center of a reasonably flat surface marked with concentric circles. A camera was placed above the marshmallow to record the change in its size, using the concentric circles as reference. These were sent to an elevation of ~30000m.
4) Discussion
We sent a marshmallow to an elevation of ~30000m. At this elevation, the decreased air pressure should be enough to cause the marshmallow to expand. According to the Ideal Gas Law, the pressure multiplied by the volume will always equal the number of moles times a constant R, 0.08206, times the temperature in Kelvin. Therefore, we can use the equation PV=nRT to estimate the change in volume of the air in the marshmallow. The initial pressure is ~0.98453491 atm, the initial temperature is 308.56K and the initial volume ~0.5 cm3. The number of moles of gasses in the marshmallow is therefore ≈
0.98453491*0.5=n(0.08206*308.56)
0.492267455=25.3204336n
n=0.01944150968
Because there are ~0.01944150968 moles of gas in the initial mini-marshmallow, there must also be the same number of moles in the marshmallow at the low pressure and low temperature conditions predicted in the experiment. We predicted that the pressure would reach a minimum of ~920 Pa, or 0.00907969 atm. Under these conditions, we expected a temperature around -50°C. This would lead to a volume ≈
0.00907969V=(0.01944150968)(0.08206)(223.15)
0.00907969V=0.35600687895
V=39.20914469cm³
This equation predicts the volume of the gasses at expected conditions under ideal circumstances. It does not account for differences in gasses’ ability to change volume, the relative amounts of gasses present, nor the elasticity of the material containing the gasses. It also does not account for any change in volume of the material, nor the volume of the material. Assuming the other substances in the marshmallow can stretch to accommodate the gasses, but remain otherwise of a relatively stable volume, we can add back the original volume of the marshmallow to predict a maximum volume of ~40cm³, or that the original dimensions of ~1cm*1cm*1cm increase by ~350% to 3.5cm*3.5cm*3.5cm.
Unfortunately, no usable data could be collected in this experiment. The camera lense being used to collect photos was smeared with glue such that it was impossible to find any information about the size of the marshmallow, and there was no backup. Other sources have determined that marshmallows typically expand when exposed to lower air pressure but none specifically measured the effects of the particular conditions measured by our experiment. This experiment would have had important implications for the possibility of using a gelatinous, air-filled substance as insulation in low pressure conditions.
5) Conclusion
Unfortunately, no usable data on this experiment was able to be retrieved, due to a smear on the lense of the camera being used to collect images of the marshmallow.
6) Figures
7) References
Kelly, D. (2020). This is how marshmallows are really made, https://www.mashed.com/196091/this-is-how-marshmallows-are-really-made/
Editors of Encyclopedia Britannica. Standard Atmosphere, https://www.britannica.com/science/standard-atmosphere-unit-of-measurement
Shaftel, H, Jackson, R, Callery, S, Bailey, D. (2020). 10 Interesting Things About Air, https://climate.nasa.gov/news/2491/10-interesting-things-about-air/
Davis, R E, Frey, R, Sarquis, M, Sarquis, J L. (2009). Modern Chemistry, https://1.cdn.edl.io/cOehbWFcrBk6QQdYLASFzSy2E1vlEKhLdRJV66pjO5nOgjIl.pdf
Engineering ToolBox, (2003). U.S. Standard Atmosphere, https://www.engineeringtoolbox.com/standard-atmosphere-d_604.html
Film experiment
by Marta Laatsch
1) Abstract
This experiment was intended to measure the effects of ultraviolet (UV) light on film. Due to the materials of the canister, UV radiation would pass through the canister and affect the film, while visible light would not. This would determine the effects of radiation on the silver halide molecules, which we hypothesized to be similar to those of visible light.
2) Introduction
When film is exposed to light, the photons in light transfer energy to silver-halide molecules. This energy causes the bonds between the silver and the halogen to break. The remaining silver forms silver ions. When film is developed properly, the opaque silver ions remain and the grains of silver-halide are washed away, forming a negative.
Starting at an elevation around 15km and dissipating at an elevation of ~35km, the ozone layer protects Earth from most harmful UV light. When vehicles are sent to elevations above the ozone layer, they are exposed to above normal levels of UV radiation.
Because UV light carries photons, much like visible light, the effects of UV light on silver-halide molecules is expected to be the same as the effects of visible light.
3) Methods
We placed the film in a canister made of a material that blocked visible light and allowed UV light to pass through, and sent it to an elevation above the ozone layer. The canister was sent to an elevation of 33,430m.
4) Discussion
This experiment was intended to explore the effects of UV light on film, and the differences between UV light and visible light. According to NASA data, film that has been exposed to above average levels of radiation, even without leaving the container, results in lower quality of film when used to take pictures in the typical fashion.
5) Conclusion
Unfortunately, we have not yet developed the film to observe the effect of the radiation. Therefore we were unable to draw a conclusion. According to results from other scientists, many types of film become blurry, result in shadows, or lower contrast.
6) Figures
Unfortunately, due to errors in the method allowing the film to be exposed to both visible light and UV light, the effects were unable to be measured.
7) References
Union University Department of Physics. (2005). The Science Guys, https://www.uu.edu/dept/physics/scienceguys/2004Apr2.cfm
Holly, M. H. (1995). The Effects of Space Radiation on Flight Film, https://pdfs.semanticscholar.org/7c0d/2dadd0fdc3d985ded783da326881d63f939b.pdf