Metric System PrimerScience uses the Metric system units as it’s standard for reporting data.

Knowing the basics of the Metric system is essential.

To report data on:

Length – the standard is the Meter

Mass – the standard is the Gram

Volume – the standard is the Liter

Temperature – Degrees Celcius

Time - Second

Metric System Primer

• Length – Meter abbreviation “m”• 1 meter, 1 m – a length approximately 39 inches• (uses – 100 meter range in Olympic archery)• The meter is subdivided into smaller units using standard

prefixes of a set value:– Kilo = 1000 - Km = 1000 meters (used to measure long

distances, for example: Distance from home to RVS campus 8.3 Km) Convert 8.3 Km to m. 8.3 X 1000 = 8300 meters

• *** simple, just move the decimal place to the right 3 spaces, that is the same as multiplying by 1000 (Very easy – even for us Math impaired biologists)

Metric System Primer• (uses – 100 meter range in Olympic archery) too far

for me

Metric System Primer

• Meter Ruler

• Divided into smaller more useful units

• Centimeter – “cm” 1/100th of meter

• Millimeter – “mm” 1/1000th of meter

Metric System Primer• Meter Ruler• Divided into even more smaller more useful units

– Micrometer = micron, the µ symbol, Greek letter, 1/1000,000 meter (length of a cell)

– Nanometer = nm, 1/1000, 000,000 (length of a molecule

Metric System Primer

Average arrow: 29 inches, or .74 m (740mm)

Metric System Primer

• Relative size of things in Biology

Metric System Primer• You must be able to quickly convert from

one metric length to another. It is easy; you only have to move the decimal place the appropriate number of places.

• Example: A cell is 0.005 mm long. What is its length in microns? Remember that a micron is 1/000,000th of a meter and that a mm is 1/1000th of a meter. Which way do we move the decimal? How many places?

• Move to the right, 3 places (same as multiplying by 1000) answer is 5.0 microns. So, 5.0 microns is equivalent to 0.005 mm

Metric System Primer• The metric unit for Mass is the Gram; symbol

“g”. This a small mass unit. A BB from your childhood Daisy Red Rider weighs about a gram.

• Useful prefixes help.– Kilo; 1000, so a Kg is 1000 grams, a tea cup poodle

might weigh only 2Kg ( close to 5 lbs)– My poodle weighs almost 6KG– Milli; 1/1000th, so a mg is 1/1000 g, a medicine

dosage might be 400 mg for IBU– Micro, 1/1000,000th, so 100 µg is ____ mg– move decimal to the ____ by ____

places– (some bio toxins, Cbot, concentrations are measured

in µg)

The “Princess”

Metric System Primer• The metric system unit for volume is the

Liter (not litter – that is for kittens)

• A liter is a large volume (about a quart)

• Useful prefixes help.– Milli – 1/1000, so 1ml is equal to .001L– Convert 350 ml to Liters. Ans: ____ L– Move decimal to the ____by ____ places– Micro – 1/1000,000, µ, so 400 µl of alcohol is

equivalent to ________ ml. – Move decimal to the ____by ____ places– (** don’t forget that 1.0 ml of water is 1.0 cc of water and actually

has a mass of 1.0 g)

Litter vs. liter

Metric System Primer

• Temperature: In the metric system, temperature is given in degrees Celsius,

Metric System Primer

• Temperature: In the metric system, temperature is given in degrees Celsius

• Useful temperatures to memorize• Human body = 37 C (98.6 F)• Water freezes at 0 C (32 F)• Water boils at 100 C (212 F)• Convert Temp from C to F = 1.8 C +32• Convert Temp from F to C = F-32 X5/9

Ice – zero degrees C body temp – 37 degrees C boiling water - 100 degrees C

Metric System Primer

• Metric standard unit for time is Second (s)• Ks = _______ seconds

ms = ________ seconds• µs = ___________seconds

ns = ______________ seconds

I’ll give you some quiz questions on the metric system for practice in class.

Review questions on line

• http://www.austincc.edu/biology

• Go to the anatomy and physiology prep. Link

• Online Self-Prep Course for the Anatomy Assessment Test  

• Go to Metric system Module and review