Name __________________________ Date _______ Pd _____ Partner’s Name ________________
Skin Receptors Investigation Lab
Introduction:
There are four different types of sensors found in human skin; pain, pressure, temperature and
proprioception (body position). These sensors are not found evenly distributed across the body’s skin. In
this activity, we will explore the concentration of pressure receptors, temperature and proprioceptions
found at different parts of the body.
Pressure Investigation-Part A
Materials:
2 Small Paper Clips
Ruler
Safety: Gently Apply Pressure to the Subject’s Skin for Two Seconds. No Stabbing!
Procedures:
Part A: Pressure- take notes where needed!
1. Unravel one paper clip into a straight line. Unravel a second paper clip into a straight line and then bend it
in half so that the two points are exactly 1 cm apart.
2. Ask the subject to close his/her eyes and look away.
3. Now decide if you will use one or two points. Be RANDOM so that the subject can’t tell whether you are applying
one or two points.
4. Using the paper clip, Gently Apply Pressure to the Subject’s Skin for Two Seconds. Be sure that if you
are using two points that they both touch the skin at the same time and with the same amount of pressure.
5. Secretly, mark the subject’s response next to the actual number of points. You must fill in five tests for
each part of the body.
6. Make sure that you switch roles for each part of the body. (Complete all 4 tests before switching roles)
Hypothesis: Part A: Pressure- take notes where needed!
How accurate do you think you will be out of the 5 tests for each body region? (Will you guess 5/5
for every region, or will it vary? Be specific!)
Data & Results: Part A: Pressure (Don’t let your partner see this table yet!)
Table 1: Subject’s Responses
Back of
the Hand
Trial #
Subject’s
Guess
Actual
Number
Tip of the Index
Finger
Subject’s
Guess
Actual
Number
Outer Side of the
Calf
Subject’s
Guess
Actual
Number
Back of the Neck
Subject’s
Guess
Actual
Number
1
2
3
4
5
Incorrect
guesses
Data & Results continued: Complete this table when you have finished all of the testing.
Table 2: My Responses
Trial #
Back of
the Hand
Subject’s
Guess
1
2
3
4
5
Incorrect
guesses
Actual
Number
Tip of the Index
Finger
Subject’s
Guess
Actual
Number
Outer Side of the
Calf
Subject’s
Guess
Actual
Number
Back of the Neck
Subject’s
Guess
Actual
Number
Table 3: Class Average Responses
Trial #
Back of
the Hand
Tip of the Index
Finger
Outer Side of the
Calf
Back of the Neck
Correct
guesses
Incorrect
guesses
Part A Questions:
1. By looking at the data you have collected, which part of the body is most sensitive to pressure? Which
part is the least sensitive?
2. What external factors could affect the sensitivity of a person’s skin?
3. Why do you think it is important for your extremities (hands, fingers, and feet) to have a greater
concentration of sensors than the trunk of the body?
4. Do you think the concentration of pressure receptors in the fingers and legs would be related to the
concentration of other receptors such as pain and temperature? Explain your answer!
Temperature Investigation- Part B
Materials:
Ice Water
Hot water
Q-tips/Droppers
Procedures:
1. Fill one beaker with very hot water (not boiling!) and another with ice water and obtain a clean
dropper.
2. Drop 1 drop of either hot or cold water on the region of the body from the table below. Indicate the
seconds it takes the subject to identify the temperature and if it was done so correctly.
3. For each region drop 1 drop 3 times (do so randomly, switching between hot and cold; for example
first drop cold, second drop hot, third drop hot, in ANY pattern)
4. Record data in the table below. Once subject has completed all body regions, switch and have the
same areas tested on second subject (yourself).
5. Calculate the average time (in seconds) it takes for each body part (using class data) to identify
temperature.
Hypothesis: Part B: Temperature- take notes where needed!
How accurate do you think you will be out of the tests for each body region? (Will you guess the temperature
accurately and how long (in seconds) will it take you? Be SPECIFIC.
Data & Results: Part B: Temperature (Don’t let your partner see this table yet!)
Table 4: Subject’s Temperature Sensitivity
Back of
the Hand
Trial #
Subject’s
Guess
Tip of the Index
Finger
Actual
Temp.
Subject’s
Guess
Outer Side of the
Calf
Actual
Number
Subject’s
Guess
Actual
Number
Back of the Neck
Subject’s
Guess
Actual
Number
1
2
3
3
2
1
3
2
1
3
2
1
3
2
1
Time (sec)
Table 5: My Temperature Sensitivity
Back of
the Hand
Trial #
Subject’s
Guess
Tip of the Index
Finger
Actual
Temp.
Subject’s
Guess
Outer Side of the
Calf
Actual
Number
Subject’s
Guess
Actual
Number
Back of the Neck
Subject’s
Guess
Actual
Number
1
2
3
3
2
1
3
2
1
3
2
1
3
2
1
Time (sec)
Table 6: Class Average Temperature Sensitivity
Back of
the Hand
Trial #
Tip of the Index
Finger
Outer Side of the
Calf
Back of the Neck
Correct
guesses
Incorrect
guesses
AVG Time
(sec)
Part B Questions:
1. By looking at the data you have collected, which part of the body is most sensitive to temperature? Which
part is the least sensitive?
2. What external factors could affect the sensitivity of a person’s skin to temperature?
3. Why do you think it is important for your extremities (hands, fingers, feet) to have a greater concentration of
sensors than the trunk of the body?
4. Do you think the concentration of temperature receptors in the fingers and legs would be related to the
concentration of other receptors such as pain and pressure? Explain your answer!
5. Explain why humans have adapted sensitivity to various temperatures in different parts of the body, over
time. (What caused the trait to evolve… why is it beneficial?)
Proprioception Investigation - Part C
Materials:
Masking tape
Blindfold
Procedures:
1. Ask the subject to close his or her eyes and extend their arms out at their sides.
2. Have them hold that position (eyes closed) for 10 seconds.
3. After 10 seconds has passed, ask subject to keep eyes shut and touch their nose with their right index
finger.
4. Ask them to put their right hand back at their side and wait 5 seconds (eyes still shut.)
5. After 5 seconds has passed, ask subject to keep eyes shut and touch their nose with their left index
finger.
6. Record data in table below. (repeat this 3 times, take the average of all 3)
7. Subject can open their eyes; test being completed.
8. Move subject to the back of the room at the starting point of tape on the floor.
9. Inform subject they are to walk in a straight line, on the tape, to the end point with their eyes shut.
10. Have subject complete line walk, giving them no directions. Once subject has passed finish point ask
them to open their eyes, turn around, stand back onto line (if wandered off), shut their eyes and walk
back to start on the line
11. Record data in table below.
Hypothesis: Part C: Proprioception
How accurate do you think you will be for both tests? Be Specific!
Data & Results: Part C: Proprioception (Don’t let your partner see this table yet!)
Table 7: Finger to nose
Subject
Yourself
Right
Left
Right
Left
Observations ?
(straight, wobbled, halfway,
etc)
Touched
Missed
Touched
Missed
Touched
Missed
Class Average #
Touched
Missed
(nothing here)
Table 8: Walking Straight
Subject
Walk Down
Yourself
Walk Back
Walk Down
Walk Back
Observations
(straight, wobbled, off line
halfway, etc)
Time (seconds)
Class Average time
(nothing here)
Questions:
1. By looking at the data you have collected, compare the accuracy to the hand that was being tested for the
class average. Does this relate to someone being “right handed, or left handed?”
2. What is the importance of this sense?
College Prep: You are to write a 2 page conclusion (typed, double spaced) telling me how the senses tested are
important human adaptations. Give examples of different human populations (based on where they live; in
different biomes). You MUST have a citation page!
Honors- A formal lab report will be made from this data. Be NEAT and organized when collecting your data.