The Biologist’s Toolkit: The Measurement Lab
Today you will move around to three different stations in order to practice important skills related to
biology. Follow the steps listed below and fill the tables with your data. Then use your data to answer
the questions provided. Remember to use proper lab safety at all times.
Station 1: Is a person’s “wingspan” equal to their height?
Imagine a person was like a bird or bat and had wings. The length from the tip of your left hand to the
tip of your right hand when holding your hands parallel to the ground is known as your “wingspan.” For
most organisms their wingspan or arm length is related to their overall body size. At this station you will
determine if your height is a good predictor of your “wingspan.”
Step 1. Find the height for each member of your group using the measuring strip on the wall. Fill in
Table 1 (below). Be sure to include units.
Step 2. Find the length of each group member’s “wingspan” using a meter stick. Enter this data into
Table 1. Be sure to include units.
Step 3. Using Table 1, determine a) the average height of your group and b) the average “wingspan” of
your group.
Step 4. Make sure all data units are in metric form. If they are in Standard or English form convert them
to metric and enter this information into Table 1. Remember that 1 in = 2.54 cm and 1 m = 100 cm.
Table 1. Heights and “Wingspan” of the Class
Group Member Name
Height (m)
Height (cm)
“Wingspan” (m)
“Wingspan” (cm)
Group Average
Answer the following questions in complete sentences:
1)
2)
3)
4)
What is the average or mean height of your group?
What is the average or mean “wingspan” of your group?
For your group, does height = “wingspan”?
How does this relationship vary among members of your group? Is there anyone who has a
shorter “wingspan” than their height? Is there anyone who has a longer “wingspan” than their
height? Why might this variation occur?
5) Why is it important to use the same units for all measurements?
Station 2: Comparing Walnut Populations
At this station you will be comparing three populations (red, green and black) of walnuts. Nuts are
another term for fruits with hard dry shells that contain seeds. By comparing measurable traits of the
walnuts you will be able to estimate the number of seeds within each walnut as well as the probability of
germination. Germination is the process by which a plant emerges from a seed. The probability of
germination compares how many seeds germinate to the total number of seeds. The higher the number
of seeds that germinate the greater the probability.
Step 1. Use the mass balance to determine the mass of each walnut in each group. Enter your data in
Table 2 (below).
Step 2. Calculate the average (or mean) mass per walnut group.
Table 2. Comparison of Walnut Populations
Red
Group
Individual
Walnut
Mass (g)
1
2
3
Average
Green
Group
Black
Group
Mass (g)
Mass (g)
Answer the following questions in complete sentences.
1. Which group has the largest individual walnut? Which group has the smallest individual walnut?
2. Which group has the largest average (or mean) walnut mass? Which group has the smallest
average (or mean) walnut mass?
3. Why is it important to look at averages and not just individual values?
4. The size of the walnut is related to the probability of germination. Use the information below to
determine which of the three populations will have the greatest amount of germination. Which
will have the most and which will have the least seeds germinate?
Table 3. Size and Germination Rate of Walnuts
Size of Walnut
0.0 g < 5.0 g
2.0 g < 7.0 g
7.0 g < 9.0 g
9.0 g < 12 g
% Germination
10
25
50
75
Station 3: Volume of Soil in Planter of Different Sizes
At this station you will be determining the volume of some containers that will be planted with either
watermelon seeds, walnuts, or grass seeds. In order to determine how many seeds to plant in each
container you will need to determine the volume of the container. Different sized seeds require different
amounts of soil to grow, with small seeds requiring less soil than large seeds. After determining the
volume of the planters you will decide how many seeds of each kind to plant in each container.
Step 1. Using the beakers and graduated cylinders, determine the volume of the 3 planting containers
by measuring the amount of water that can fit within each container. Enter the data in Table 4.
Table 4. Container Volume and Seed Numbers
Container
1
2
3
Volume (mL)
Number of
Watermelon Seeds
Number of
Walnut Seeds
Number of
Grass Seeds
Step 2. Different types of seeds require different amounts of soil to germinate. Using the information
below determine how many seeds of each kind may be planted in each container and enter the data
into Table 4 (above).
Table 5. Soil Requirements for Different Seeds
Type of Seed
Watermelon
Walnut
Grass
Volume of Soil Needed per Seed
50
350
10
Answer the following questions in complete sentences.
1. What does the volume of soil required for each seed suggest to you about the size of the seed?
Which seed is likely the largest? Which is the smallest?
2. If you wanted to plant all three species of plants in the same container which container would
you use and how many seeds of each plant would you use?
Station 4. Walnut Mass and Volume
Step 1. Pick 3 walnuts from the jar. Write a number 1-3 on each walnut.
Step 2. Find the volume of each walnut using displacement. Displacement is what happens when you
add an object to a beaker or graduated cylinder of a known quantity of water. The object takes up room
and displaces the water changing the overall volume. You can calculate the volume of the object if you
know the beginning volume and the final volume, using this equation: final volume – original volume =
volume of the object. Enter this data in Table 6 below.
Step 3. Take the 3 walnuts up to the scale in Station 2 and find their mass. Enter this data into Table 6
below.
Step 4. Calculate the density of each walnut. Remember that density = mass/volume. Enter this data
into Table 6 below.
Step 5. Find the average mass, volume and density for your 3 walnuts.
Volume, Mass and Density of Walnuts
Individual Mass
Walnut
(g)
1
2
3
Average
Volume
(mL)
Density
(g/mL)
Answer the following questions using complete sentences.
1.
Which walnut has the largest mass? Which has the largest volume? Is it the same walnut?
2. Could it happen that the largest walnut by mass was not the largest walnut by volume? Why or
why not?