Read and analyze an article that uses an physical model, and present it to your classmates. Select an article from the list on this page (link). You are also welcome to use an article you find on your own, as long as it meets the criteria for a scientific model.

Article critiques:

Create a new thread and post a critique of an article. Your critique should be at least 300 words and should address the following questions:

  • How would you describe the model?
  • What is it made of?
  • What does it do?
  • What research question(s) did the authors investigate?
  • What did the researchers learn by using this model?
  • What were their results?
  • How did the researchers make sure their model is credible?
  • Do you think it is trustworthy enough to investigate their research question(s)?
  • Was a physical model a good choice for this study, in your opinion? Include a link or full citation for your source material.

Reply posts:

Next, write substantive, thoughtful replies to at least two of your peers’ posts. Reply posts should address the following prompts:

Do you agree with the assessment in the original post? If you do agree, indicate what convinced you. If you don’t agree, explain why.

What other research questions might be addressed by the model?

What other types of models might address the research aims? You may also share any prior knowledge or personal experience you have with the topic to enrich the discussion.

Post 1 to reply:

The article that I chose simulates an automobile crash with the first pregnant crash dummy. I chose this article because many of my friends recently gave birth or are currently pregnant, so I thought it would be an interesting read and maybe I could give them a few facts about driving while pregnant. The purpose of this simulation was to test a “hybrid insert” that goes around the woman’s belly and evaluate how well it does against impact towards the fetus and its maternal compartments. The item is supposed to be an “insert that has an elasticized vinyl uterine shell” (Pearlman, 1996).

This model evaluates the points of impact on the fetus on impact, and they tested at various speeds. The placement of the seatbelt was also a crucial factor. Having the seatbelt laying over the belly (improper placement) resulted in three to four times the force of impact on the uterus at all different speed trials, whereas having it under the belly (recommended placement by The American College of Obstetricians and Gynecologists and the National Highway Traffic Safety Administration) caused less trauma. The impact it had on the fetal head and thoracic acceleration (gravity) at an increment of 5mph each increased 100% each time. By experimenting with this, the loss of pregnancy was still inevitable, unfortunately. Many pregnant women involved in minor accidents lose their baby after the fact most of the time.

The article really highlights the fact that seat belts are especially crucial. It also points out that some women don’t like to wear seat belts or reposition them improperly for comfort. I think it’s unfortunate for pregnant women to suffer such inconveniences. I find this article to be credible and trustworthy enough to investigate their research questions. I think in this modern time of technology, we should be able to invent a safe, effective, and comfortable seat belt for pregnant women. This physical model was a good choice to study in my opinion! I might think that because of my bias towards pregnancy. I only want the mother and baby to be healthy and safe, before and after birth.

References

Pearlman, Mark D., and David Viano. “Automobile Crash Simulation with the First Pregnant Crash Test Dummy.” American Journal of Obstetrics and Gynecology, vol. 175, no. 4, 1996, pp. 977–981., doi:10.1016/s0002-9378(96)80036-6.

Post 2 to reply:

In this physical model they used different layers of snow on a shake table to demonstrate how earthquakes can affect snow avalanches. My understanding of the experiment is that they used actual snow and maintained a temperature of -10 degrees celsius in their test environment. This snow was then put on a shake table that moved horizontally and then vertically as well as the experiment became more complex.

One of the biggest questions they seemed to be researching was how a weak layer of snow impacted if and the way an avalanche occurs. From there they were researching the different impacts that different movements at different angles had on the snow. They were asking how the snow reacted to several kinds of oscillations. They learned a lot about the strength in the layers of snow and how they strengthen or weaken when they are shaken or have stress put on them. I think they made this model credible by looking at several different types of motion.

As we now know earthquakes are not all the same and they run their course for a range of amounts of time, this experiment allowed for that. It also allowed for the fact that avalanches happen on slopes, they didn’t simply shake now on a flat surface but tested several angles. It is by no means a perfect investigation but it is a simplification of the real world that is generating data that can be used. I think for the reasons above this is a fairly trustworthy experiment. They also recognize that there is more research to be done if we really want to understand these questions.

Finally I think this was a good choice of model for this study. I think it would be cool to see it on a slightly larger scale, for example a larger shake table, but they were able to demonstrate numerous scenarios and come with data. Podolskiy, Evgeny A., Kouichi Nishimura, Osamu Abe, and Pavel A. Chernous. 2010. “Earthquake-Induced Snow Avalanches: II. Experimental Study.” Journal of Glaciology 56 (197): 447–58. https://doi.org/10.3189/002214310792447833.

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