Chemistry I
Lab: Drawing a Scale Model of the Atom
Introduction
The mass of an atom is concentrated in its nucleus – a small, dense, sphere with a diameter
about 1/100,000 that of the atom. Most of the size of an atom is apparently empty space!
How can we translate the dimensions of the nucleus and the atom to things we can see and
understand? In this activity, we will use various sized balls and a map of Celina, Ohio, to
draw a scale model of the atom.
Concepts
• Atomic nucleus
• Atomic radius
Materials
• Two of the following: basketball, baseball, softball, tennis ball, racquetball, etc...
• Maps of Celina and surrounding area
• Metric ruler
• String
• Tape measure (optional)
Safety Precautions
Although the materials used in this activity are considered nonhazardous, please observe all
normal laboratory safety guidelines.
Procedure
1. Using a length of string and a ruler (or the optional tape measure), determine the
circumference of a basketball in centimeters to three significant figures.
2. Rearrange the formula for the circumference of a sphere (circumference = 2 π r) to
solve for the radius (r). Use this equation to calculate the radius of the basketball in
centimeters to three significant figures.
3. Imagine that the basketball represents the nucleus of a carbon atom. The radius of a
carbon atom is 26,000 times larger than its nucleus. (Some atoms are approximately
100,000 times larger than their nucleus). Calculate the radius of a carbon atom that
would have a basketball sized nucleus. Record the radius in both meters & kilometers
to three significant figures.
4. Select the appropriate sized map provided and draw a circle on the map to illustrate
the size of a “city atom” compared to its basketball sized nucleus. Choose a map that
will be at least 1/3 covered with the atom. Use Celina High School as the location of
the map for the center of the nucleus. Hint: each map has a scale shown in the
corner. Write all of your calculations on the map page you have selected.
5. Now, choose a different sized sports ball and repeat steps 1-4. You should have two
scale models and two sets of calculations when you are finished. Write your name on
them, staple them together and turn them in.
Map 1
Name______________Date__________
Show calculations here:
Map 2
Name______________Date__________
Show calculations here:
Map 3
Name______________Date__________
Show calculations here:
Map 4
Name______________Date__________
Show calculations here:
Map 5
Name______________Date__________
Show calculations here: