Sense-able! Background Information: Your skin is the largest organ in your body, and your skin has three layers. The first layer on the outside of the skin is the epidermis. The second layer of the skin is the dermis. The dermis is the layer of the skin that holds the sensors that tell your body when something is hot or cold, for example. The bottom layer is called the subcutaneous. There are little things in your body that sense when you are being touched, called nerves. Right now you probably cannot feel your clothes anymore, because your body has gotten use to the feeling and weight of your clothes. Purpose: To discover the different aspects of the sense of touch; such as the sensitivity of touch and pressure sensors in the skin. Hypothesis: The senses in the body are different in different locations and the sensitivity of touch also changes from location to location. Materials: ● Markers (at least 2 different colors) ● At least 6 pennies ● Stop Watch ● Rulers Procedure: Station 1: Marker’s Touch 1. Let a student choose what part of their arm or hand that they want to test. (Examples: finger tips, palm, top of hand, etc.) 2. Choose a second student to conduct the test. 3. Have the first student close their eyes with a marker in their hand. 4. Have the second student put a dot, using the marker, on the place that the first student chose. 5. After the second student puts the dot on the first student, the first student, keeping their eyes closed, tries to put a dot in the same place as the second student. 6. Once both students have made a mark using the marker, the first student can open their eyes and measure the distance in centimeters between the two dots. 7. Record the part of the arm or hand that the test was conducted and the distance between the two marks. 8. After this is done, compare with other students and see the differences! Created By: Meghan McCaskey, Ashley Martin, Kierra Holst Coppell High School Anatomy 2011
Station 2: Coin Stacking 1. Place one penny on your forearm with your palm facing up. 2. Time how long it takes until you cannot feel the penny on your arm anymore. 3. Write down the time in the table below. 4. Now place five pennies on your forearm with your palm facing up. 5. Time how long it takes until you cannot feel the five pennies on your arm anymore. 6. Write down the time in the table below. 7. Compare your time with the times of the other students. Station 3: Feelings 1. Have one student lay their arm on the table with their palm facing up. 2. Have the student close their eyes. 3. Have a second student draw a line up the first students arm in swirling motions. 4. Have the student with their eyes close guess when the person drawing the line is at the middle of their arm. 5. When the student says stop, measure the distance between the middle of the arm and the spot where the student says stop. 6. Write this distance in the chart below. Data Tables: Station 1: Marker’s Touch Student
Part of Arm or Hand
Distance between the 2 dots
Station 2: Coin Stacking Student
Time with One Penny
Time with Five Pennies
Station 3: Feelings Created By: Meghan McCaskey, Ashley Martin, Kierra Holst Coppell High School Anatomy 2011
Student Distance between Middle of the arm and Spot where student guessed was the middle
Data Analysis Questions: 1. How did your distance in the last lab compare to other students?
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2. How would having less nerves affect what you feel?
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3. In the marker station, which spot was the most sensitive to to touch? Why?
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4. Why could you not feel the pennies after a certain amount of time?
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Teacher Notes: Created By: Meghan McCaskey, Ashley Martin, Kierra Holst Coppell High School Anatomy 2011
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For stations: Table one should have markers and a ruler. Table two should have at least 6 pennies and a stopwatch. The third station, should have a ruler. Use washable markers. Try to split the students into three equal groups. You could introduce subject by talking about how the students cannot feel their clothes because their brain suppresses the signal. For higher level students, you could try a two-point differentiation test. With a pair of dull tip safety scissors, adjust the angle of the scissors and compare how the length between the two points affect the number of points that the students feel.
Created By: Meghan McCaskey, Ashley Martin, Kierra Holst Coppell High School Anatomy 2011