A week before Thanksgiving this year, I was not so lucky to have stepped barefoot on a big piece of broken glass on kitchen floor. The glass was a leftover piece of an olive oil bottle that fell and broke in the kitchen and was overlooked in the cleanup process (it was at that moment that I appreciated my mom’s advice to always wear slippers in the house, just a little too late). It was a pain I will never forget.
Being a science teacher, I immediately recalled the sensitivity of the foot in relation to nerves when this injury happened and knew why I was in so much pain and that I was in for a painful recovery. A month later, I still recall that sharp pain, due to the sensitivity of my poor bare foot and sensation there is not the same as it was before due to nerve damage. This brought me to wanting to suggest to you a lab that you can do with your classes, that will test which parts of the human body are more the most sensitive.
Now that we are entering the second half of the school year, biology classes are most likely to be getting ready to start studying the human body systems. Usually, the human body systems are the last units covered in biology classes, later in the spring semester. In health classes, they may be taught in the fall or spring semester, so if this unit has passed you by, you may want to consider doing this with your classes next year. Whenever you want to try it, this lesson is one that will go with your nervous system unit.
Have you ever heard of the two-point discrimination? If not, there is a good chance that your students have not either and this would be a good thing to introduce to then when studying the nervous system. The two-point discrimination test accesses the ability to be able to discern that two close by points placed on a small area of skin are indeed two points and not one point. The person being tested should not be looking at the object when it is placed on the skin.
In the medical field, the two-point discrimination test is sometimes performed by neurologists during a neurological sensory exam to test for peripheral nerve damage. Some reasons a neurologist may perform this test on a patient is if they suspect a problem with the sensory information coming into the skin, problems with interpretation of sensory information, or problems with pathways to the brain. Say a patient suffered a severe cut (as I did with my foot). The doctor can use this test to check for nerve damage after the injury and may perform it a second time weeks later after healing has taken place to see if the damaged nerves have regenerated.
Students can perform this simple test on another student in class to find out which body parts are more sensitive than others-great lab for those students who are aspiring to be doctors, or for those who are curious to learn a little more about their bodies.
In this hands-on-activity students will test which body parts are more innervated using a bent paper clip, metric ruler, and a buddy to work with. The lab and only requires a few materials that you most likely already have on hand at your desk.
In this lab is that students will get more practice with dependent and independent variable and with forming a hypothesis (not exactly as stated in a science experiment, but in a similar way where they circle a choice for their hypothesis). The mini experiment set up portion of the lab that students will answer prior to performing the test is in the printable worksheet they will answer.
Students will choose several body parts to test using the paper clip test (this method for testing two-point discrimination is in the lab procedure). You may want to tell students which body parts to test by giving them a list on the board. You can decide if you want them to test the same places on the body, or if you want them to choose which body parts they test. Remind them that the body parts must be readily accessible and classroom appropriate parts to test- of course. The back, arm, top of hand, palms, fingers, calf, shin, top of foot, bottom of foot, lips, face, shoulder are possible testing spots you can recommend-this is up to you to decide.
Students will record their data on a worksheet provided in this two-point-discrimination lab. Everything is ready to go for you in this lab. At the end of class, students can share their results with the class, and turn in their lab data sheet to you.
Extension for the Real World
Have you heard of the Shotblocker? The Shotblocker is an innovative, U-shaped device that has tiny bumps on one side of the U-design. If used correctly, it is supposed to block or minimize the discomfort felt during an injection, like when you get a vaccine. The Shotblocker works by saturating sensory signals around the injection site, so that a person receiving a shot should not feel the sting of the needle that is usually felt during a vaccination or blood test.
I bought this for my daughter a few weeks before her wellness checkup because she was going to have a few vaccines and she is very terrified of shots...so much that in the past we have had to have the clinic's on site psychologist come in during her visits to help calm her and convince her to do it (A huge ordeal!). But, I am hoping not anymore, because we tried this device at her last visit and let me tell you-it really did help! She did not feel that stinging pain when the needle entered her skin! No tears. She was able to tolerate the shots!
After learning about it, I knew I must share this neat device with you, since it relates perfectly to the nerves and integumentary system discussions. It will be a great addition to this lesson, and most of your students probably don't even know this product exists. I wonder if they have heard of numbing sprays or creams as well? You can even talk to them about how these products act on the human body as well to reduce pain for the individual.
Show students one of these during class and ask them how they think this device might lessen the pain of a shot, or will it? What do they think, will it work, or not? Have them explain their reasoning. Then, have them try it for themselves by applying and pressing the Shotblocker on their own skin while another student presses one end of a paperclip in the middle of the Shotblocker’s U, as shown in the picture below (don’t let them press too hard of course!). They can try different parts of their bodies, like in the Two-Point Discrimination Lab, to see if it worked better in certain areas of the body.
Then have them press the end of the paperclip on their skin without using the Shotblocker and let them see if they feel more discomfort in that spot without it. Afterwards, they will switch places with their partner so that both students can see if they can feel a difference between using the device and not using it. Make sure they use it correctly.
I bought mine for around $37, a little pricey for a pack of five, but they are reusable as long as you wash it after each use, so I think it is worth it. Besides, once you have these, you can use them over and over in your classes throughout the years. And the good thing is, too, is that you should you ever need to get a shot yourself, you've got one of these to use. :)
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