Question

• How does atmospheric pressure affect the size of a marshmallow?

Hypothesis

If atmospheric pressure is decreased, the size of a marshmallow will increase.

Variables

Independent Variable: Atmospheric Pressure

Dependent Variable: Size of the Marshmallow

Controlled Variable: Camera Distance From Marshmallow

Procedure

Step 6: Collect the atmospheric pressure data for the time each image was taken from the Z-log device.

Step 7: Compare the size of the marshmallow with the atmospheric pressure.

Data

Unfortunately, there was a problem with the GOPRO camera. For some reason, the camera only caught about half of the marshmallow. Enough of the marshmallow was still visible to determine if the size changed with changes in pressure. Also, the camera only took pictures for 67 minutes before the battery failed. It was charged, but it was not connected to the battery backup.

Analysis

It is difficult to analyze the data whenever web page software readjusts the size of an image to fit predetermined dimensions. The images in the data section above are close to the original size, but the web page software made slight changes to the dimensions. The correct dimensions of each picture are listed under each picture. In order to create a better representation of the data, in Microsoft Word, the image of the marshmallow at launch and the final image were placed next to each other. Then, the snipping tool was used to create a picture of the two images together. There were no changes made to the dimensions of the images in Word. This image is located directly above this text. The web page software made the entire image larger to fit a predetermined block. Although the image size was enlarged, the relative size of each marshmallow can be observed. The last image is much larger than the first image. If the number of pixels are compared, the last image is 19.5% larger that the first image.

The pressure difference between when the launch occurred and the time the last image was taken was 21.503 in of Hg. This is a 73.5% drop in atmospheric pressure.

Conclusion

In this experiment, the data supported our hypothesis that the marshmallow would expand as the atmospheric pressure dropped. The final image was about 19.5% larger than the image at the launch. When selecting the images using the snipping tool, an error of about 10 pixels for both the length and the width. This means that the product of the dimensions of the image could be off as much as 100 pixels. This amount of error will not change the the interpretation of the results. If we were to repeat this experiment, we would make sure that the GOPRO is fully charged and correctly positioned before the flight. A ruler could be placed near the marshmallow to provide a way to measure changes. A permanent marker could be used to draw lines on the marshmallow. Changes in these lines could be observed in the video.