Name ____________________________ Date _________________ Period _____ Score out of 25_____
Corrected by ____________________________
Bone Density Lab
Bones and muscles work together to provide a structural framework for movement.
Are the bones of animals that walk denser than the bones
of animals that swim or of animals that fly?
The structure of each body part of an organism is related to the function of that body part. For example,
animals depend on specialized body parts for movement. Animals contract and relax muscles that are
attached to bones in order to move. Some animals have legs, wings, or fins to move around. In
vertebrates, most movement is the result of bones and muscles working together. Bones that support a
lot of weight are thick and heavy, such as in elephants. Bones that do not support a lot of weight are light,
such as in the wings of birds. The bones of vertebrates have many similarities. Compare the bones of a
mammal, a bird, and a fish and note how differences in their structures relate to the functions of these
bones.
Materials
• balance
• beef bone
• chicken bone
• fish bone
• graduated cylinder
• weight
Procedure
A. Find the mass of the mammal bone.
- Use a balance and record this value in Table 1.
Table 1: Mass, Volume, and Density of a Mammal Bone and a Chicken Bone
Bones
Mass (in g)
Volume (in cm3)
Density (in g/cm3
Mammal
Chicken
B. Find the volume of the mammal bone.
Fill a graduated cylinder about 500mL of water and add the weight. Note the water level in the
cylinder and record in Volume Calculations Table. (Note: 1 mL = 1 cm3)
Submerge the bone and note the new water level. This reading is the volume of H2O with the
bone. If the bone floats, put it under a weight to hold it down.
- Subtract this number from the volume of H2O without the bone. Record the difference in Table
1.
- Repeat steps A – D using a chicken bone.
Volume Calculations Table
Beef Bone
Chicken Bone
Volume of H2O with bone
Volume of H2O without bone
Difference
C.
Find the density of both the mammal bone and the chicken bone.
- Density is the mass of an object divided by the volume of the object.
- Calculate the density of this bone. Record this value in Table 1.
Analyzing Results
1. Which bone had the greater density?
____________________________________________________________
2. Describe the relationship between the density of the bones and the size of muscles needed to
move the bones by completing this sentence:
Larger muscles are needed to move ____________________________________ bones.
3. Given a bird the same size as mouse. Would the bird have the same shape and size muscles as
the mouse?
__________________
4. Which would need larger muscles and why? _________________________________
____________________________________________________________
5. Complete the table below by comparing the bone density of a mammal bone, a bird bone, and a
fish bone. (The fish bone has been done for you.)
Rate the
density of
the bone
from least
(1) to
greatest
(3)
Organism’s type
of movement
Where the
organism
primarily moves
How is the density of the different
bones related to how the organism
moves and where the organism
lives and why?
Mammal
bone
Bird
bone
Fish
bone
1
least
dense
swims
in water
The bones of a fish must be light
and flexible so that the fish can
swim without sinking. Bones do
not have to support the weight of
the fish’s body in the same way
that the bones of a land animal do.