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Unit 2
Scientific Notation and Unit Conversion
BIO 123
Mathematical Methods for the Natural Sciences
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Introduction
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In this unit, you will learn the valuable skills of scientific
notation and unit conversion.
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Why do you need to know scientific notation?
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Scientific notation comes in handy when you are dealing with very
small or very large numbers. It basically saves you from writing
many 0’s.
There are about 7,000,000,000 people on earth (that’s 7 billion).
To save myself from writing out those 9 0’s, in scientific notation I
could just write 7 x 109.
Why do you need to know unit conversion?
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I think a more appropriate question is, “why DON’T you need to
know unit conversion?”.
If you are a scientist of any kind, unit conversion will be a part of
your life, and it’s best that you embrace it as soon as possible.
There is an example on the next page!
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Unit Conversion Example
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Before you do anything, watch this YouTube video (it’s only 4
minutes long) giving a great introduction to unit conversion:
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http://www.youtube.com/watch?v=XKCZn5MLKvk
If you haven’t noticed yet, I really love YouTube.
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Unit Conversion Example
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You are a medical doctor. You have a patient that has an
underactive thyroid gland, which means she is feeling
fatigued and is at risk for serious medical problems in the
future, such as heart disease, if it isn’t managed.
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To treat underactive thyroid, you give synthetic thyroid
hormone. The optimal dosage is 1.7 μg/kg. However, the
pills only come in mg, and you only know the weight of your
patient in lbs.
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Keep in mind that if you underdose her, she will continue to have
symptoms and possible die of a heart condition later in life.
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If you overdose her, she will have insomnia and heart palpitations.
It is important that you can do unit conversion so that you can
properly treat your patient.
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Unit Conversion Example
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In the coursebook, you’ll find that 1000μg = 1 mg, and that 1
pound = 0.4536 kg. Your patient weighs 130 pounds.
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Here is how I did it: