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1. Note that chart is on a logarithmic scale.
That is, each major size marker is 10 times greater than
the previous one. For example, 1 cm is 10 times longer
than 1 mm, 1 mm is 10 times longer than 100 micrometer
(0.1 mm), 100 micrometers is 10 times longer than 1
micrometer, etc.
2. Assume the following typical sizes for the
purposes of this demonstration:
frog egg = 10-3 meters (.001 meters or 1 mm)
large cell = 10-4 meters (you finish the
math on worksheet)
large bacterium = 10-5 meters (you finish
the math on worksheet)
large virus - 10-7 meters (you finish the
math on worksheet)
large molecule = 10-8 meters (you finish
the math on worksheet)
3. Let a 2 liter plastic cola bottle represent
the size of a frog egg. Fill the bottle with water and use
a proportional amount to represent the size of each of the
other items. Example: a large cell is 1/10 the size of a
frog egg, so you would use 200 ml of liquid to represent
the size of a large cell.
4. Calculate how much liquid you would need to
represent the size of a large bacterium, a large virus,
and a large molecule.
5. Put the calculated amount in a container so
you can actually see the differences in amount.
Containers and measuring devices needed: 2 liter cola
bottle, a beaker than can hold and measure up to 0.5
liters, a 1 ml syringe (insulin syringe), and a microliter
syringe (you could use a 1 ml syringe to estimate but the
amount will not be accurate). For the last two volumes of
liquid, the amount of water you would need is so small you
can just squirt it on a table top.
Access the Student Journal
for this Activity
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1.
Review how you calculated the differences in size