This semester our class participated in a near space experiment. This consisted of putting a variety of different experiments into boxes (or modules), attaching them to a weather ballon, and launching the balloon into near space. We ran a variety of tests and collected observations.
Our Research Questions
Each group was assigned to formulate two research questions to test. Our first question included testing how the elasticity of a rubber band would change after being exposed to extreme temperature changes. Our second question looked at how the color/texture of a regular apple slice and the color/texture of an apple slice coated in lemon juice would change due to a decrease in oxygen levels.
Materials and Procedure
Experiment 1
For the first experiment, the only materials needed are the rubber band, a tape measure or ruler, and tape to hold it in place in the module. The rubber band should be a standard, classic rubber band. This experiment is measuring the change in elasticity of the rubber band. Elasticity is defined as the ability of an object to return to its normal or beginning shape after being stretched out. After the rubber band is sent into near space, its elasticity will be re-evaluated and compared to its original value. This value is measured and recorded in centimeters. To start the process of setting up the first experiment, begin by measuring the diameter of the rubber band in centimeters rounding to the nearest tenth using the tape measure/ruler. Then, secure the rubber band to the bottom of the module using a piece of clear scotch tape in only one spot on the rubber band to ensure that it’s not restricted and can still stretch. This experiment is now ready to be launched. After recovering the module, remove the tape from the rubber band if it isn’t already. Then, using the same tape measure/ruler as before measure the diameter of the rubber band again and record the value in centimeters rounding to the nearest tenth. This completes the first experiment.
Experiment 2
For the second experiment, the materials needed are an apple, lemon juice, a knife to cut the apple into slices, a tape measure or ruler, two Ziplock bags, a small and pointy object to poke holes in the bag with, and tape to secure the bags to the module. There are many kinds of apples that differ in color and type. For this experiment a red apple was used, and more specifically it was a gala. It’s predicted that the color of the apple slice will change with decreased oxygen levels as the altitude increases. Start by cutting an apple into 16ths. Take one of the slices and dip it into lemon juice. Then place that apple slice with the lemon juice on it and put it in a Ziplock bag. Put a regular apple slice into a separate plastic bag. Zip the bags and poke small holes in them to ensure oxygen is able to circulate. Then attach the bags to the module using a clear piece of scotch tape. It is now ready to be launched. Once the module is recovered, remove the piece of tape, open the bags, and inspect the apple slices. The only measurements here are observing the color of the apple slice and possibly any texture change (dried out or slimy) and no numerical value is recorded.
Design/Layout
Figure 1: Above is what the design for the module looks like from the front.
Figure 2: Above is what the design for the module looks like from the back.
Figure 3: Above is what the design for the module looks like from above.
Results/Findings
Experiment 1
Before the flight, two measurements of the rubber band were taken. The rubber band was laid out in a circular shape in order to attain an accurate and consistent measurement. First, the diameter was measured to be 6.20 centimeters. Then, the rubber band was stretched until it gave resistance, and we measured a length of 40.0 centimeters. After the launch, the diameter of the rubber band was found to be 6.30 centimeters. The rubber band was stretched again and the length was measured to be 42.5 centimeters. It's important to note that the rubber band shouldn't be stretched before taking this measurement in order to help prevent the results from being altered.
Experiment 2
Before the launch, two apple slices were observed. One was a regular apple slice, and the other was coated in lemon juice. They both had a pale and yellow appearance with no discoloration on any area. The regular apple slice wasn't dry, but also wasn't slimy. It was the average/regular consistancy of an apple. The apple that was covered in lemon juice was wet, but did not have a slimy texture. After the launch, the regular apple was brown and darker overall. It was very dried out in some places and wasn't wet to the touch. The apple that was coated in lemon juice might have been a slightly darker shade of yellow, but it wasn't brown. This apple slice was very wet to the touch and could be described as slimy.
Conclusions
In the first experiment, the measurements were very similar when looking at the rubber band before and after. Our hypothesis was that the rubber band would change in diameter and stretch to a different length due to temperature change. More specifically, it was predicted that both measurements would increase. When comparing the results, the diameter measured after was only 0.1 centimeters larger than the original. This could be due to the temperature change, however it could also just be due to an inconsistency when measuring. The difference in length when the rubber band was stretched was greater after the launch by 2.5 centimeters. Again, this could be due to the temperature change, but it could also be due to it being hard to keep the stretching of the rubber band consistent.
For the second experiment, no numerical values were recorded. We predicted that the apple slice that was left alone would maybe turn a little turn brown and dry out, while the apple slice coated with lemon juice would just turn a little darker shade of yellow. This is due to enzymatic browning (an oxidation reaction). However, since the oxygen levels decrease as the balloon gets higher, we predicted that the results wouldn't be drastic because they would be less exposed. After the launch our predictions turned out to be mostly correct. The regular apple had turned a slightly brown but it was very dry in some places. The one coated in lemon juice may have turned a darker shade of yellow but it didn't appear brown. This is due to the lemon juice creating a barrier between the apple and the oxygen in the air. It also came back more slimy rather than just wet. Overall, the color and texture of the apples weren't super drastic, which we believe is due to being exposed to less oxygen as the balloon increased in altitude.
Thoughts for future trials
There were a few things that could have been done to make these experiments more accurate. For the first experiment we could make sure to have an accurate measurement of the rubber band before, so that we are able to make an accurate comparison after and be more specific. It can also be difficult to judge how much the rubber band is stretched and to use the same strength to stretch it after the flight as you did before. It might be best to find a different test to use. For the second experiment, it would be interesting to compare the apple slices that were sent up in the balloon to two apple slices (from the same apple) that are left on the earth's surface. This way we can compare how the apples look when they're exposed to less oxygen compared to how much they're normally exposed to.