The Hair Lab
Introduction
 Problem: Which type of hair: ___________, __________, or ________ is the widest?
 Hypothesis
 Experimental Design
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Variables
o
The manipulated variable is...
o
The responding variable is...
o
Three controlled variables are...
Materials
o
Compound light microscope
o
1 Slide
o
1 Coverslip
o
1 Dropper with water
o
3 samples of __________ hair
o
3 samples of __________ hair
o
3 samples of __________ hair
Procedure:
1. Make a wet mount slide of the first type of hair, using a couple of drops of water and
only one hair.
2. Put the slide on the stage of the microscope and focus it on low, then medium, then
high power. Always center the hair in the field of view before you move to the next
power.
3. Make a scientific illustration of the hair UNDER HIGH POWER.
4.
Calculate the width of the hair.
5. Record the data in the data table
6. Clean the slide and repeat steps 1-3 with two other samples of the same kind of hair.
7. Repeat steps 1-6 with two other hair types.
 Data and Results
Hair Type
Width of Field
of View (µm)
Number of Times Hair Fits Across Field of View
Hair 1
Hair 2
Hair 3
Width of Hair
(µm)
Average
 Conclusion
1. What problem were you trying to solve?
2. Which type of hair was the widest (use your data to prove this)?
3. Was your hypothesis correct?
4. Summarize the widths of the hair you measured.
5. Make an inference to explain why that particular type of fur is wider than the others.
6. What errors may have occurred in your investigation (uncontrolled variables)?
7. How could you improve the results you get in the investigation?