It is often neglected that different areas of the body have dissimilar levels of sensitivity, for example the legs vs. the forearm; this is known as the body’s sensory receptors. Some of the body’s sensory receptors specialize in temperature, while others specialize in touch. In this lab, students are given the task to infer and prove which area of the skin is more sensitive to touch: the finger tips, the forearm and the the back of the hand. We were given a paper clip and a ruler and were asked to identify whether two ends of the paper clips were used to “poke” the area or one.
To complete this lab, students were given 3 charts to fill in (shown below)
To complete the charts, we followed these steps:
- Adjust the paper clip so it is 2 cm apart
- Make sure your partner’s eyes are closed so she is more aware of the sense of touch
- poke your partner’s hand for a total of ten times- 5 with two ends and 5 with one end
- Record the data are your partner tells you how many ends she thinks there is
- complete the same steps for 1.5 cm, 1 cm, 0.5 cm and 0.3 cm on the forearm and finger
After completing the lab, here is the data I recorded from my partner Kaitlyn O’s observations.
After testing the data, my hypothesis did not support my data as I had originally predicted that the back of the hand with be the most sensitive because it is the thinnest area of skin. In actuality, the finger had the most sensitive receptors which now makes sense because that is the main reason for the human’s anatomy of fingers. With that being said, I think humans have higher touch densities in certain areas of the skin because it is not necessary in some areas, for example, the leg does not have to be extremely sensitive to touch.
Overall, my partner and my data matched up fairly well. We both experienced a higher level of sensitivity at the fingers as the data for the “end felt” was more accurate and close to the description.
While there is little room to mess up during this experiment, factors that could have lead to a variation of sensitivity include: areas that are used more, which makes the skin tougher, genetic composition, and past burns. For example, a person playing guitar or video games may make one more sensitive to certain buttons as they are constantly in use and develop a denser sensory receptor.
You might have heard of the saying “thick skin” which usually refers to one who does not give- in or forgive easily. This can relate back to a person’s sense of touch as places with thicker skin are not “felt” as easily.
Another every day issue revolving the sense of touch regards automobiles. It is often a distraction for drivers to control knobs or buttons such as the volume button or when changing radio stations. To solve this problem, dashboard designers could remove the whole “touch” system completely and install a voice activated option, or redesign the dashboard so the knobs are controlled by touch pads that adjust according to how much pressure is applied to the surface.
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