Ways of Measuring…

• List as many ways of measuring as you can • Compare with a partner

M E T R O L O G Y

The Metric System

The metric system was devised by French scientists in the late 18th century It was- and is- intended to maintain a worldwide standard for measurement (vs. English Standard) It is based on the number 10 Because of this, it is easy to convert from unit to another Why do we want to be able to convert units?

Linear Measurement (standard unit = meter) Prefix Milli Centi Deci Meter Deka Hecto Kilo Abbreviation mm cm dm m dk hm km Fraction 1/1000 1/100 1/10 1/1 10/1 100/1 1000/1 Decimal .001

.01

.1

1.

10.

100.

1000.

Estimating Metric Units • A mm is about the width of your pencil lead • A cm is about the width of your pinkie finger • A dm is the length of a cassette tape • A m is about the height of a door knob • A dk is about the length of this classroom • A hm is about the length of a soccer pitch • A km is about the distance from RMS to Riverside Park

Unit Comparison OBSERVE !

• 10 mm = 1 cm • 100 mm = 1 dm • 1,000 mm = 1 m • 10,000 mm = 1 dk • 100,000 mm = 1 hm • 1,000,000 mm = 1 km

Unit Comparison- con’t…

• 10 cm = 1 dm • 100 cm = 1 m • 1,000 cm = 1 dk • 10,000 cm = 1 hm • 100,000 cm = 1 km • 10 dm = 1 m • 100 dm = 1 dk • 1,000 dm = 1 hm • 10,000 dm = 1 km

If all else fails, try this… km <> hm <> dk <> m <> dm <> cm <> mm Actually use your finger to move the decimal This allows you to convert from one unit to another easily

Reading a Meter Stick Be sure to close one eye and get object lined up at eye level. What is the EXACT length of this object?

Be sure to get at eye level… Why?

How tall am I anyway?

ALWAYS… • Estimate • Measure twice • If you get the same measurement, then you can be reasonably assured you’re correct • What should you do if you DON’T get the same measurement?

W E I G H T j u s t a m i n u t e !

Weight VS. Mass • Weight is the measure of gravity • It can change depending on the body that is influencing the object • You weigh less on a mountain top than at sea level • Let’s calculate our weights on different planets… Earth’s Moon: .16

Jupiter: 2.60

Mars: .39

Pluto (dwarf planet): .05

So, what’s MASS?

• Mass is the measure of matter in an object • It will not change depending on location • It’s that property that makes mass ideal for science • In the metric system, mass is measured in GRAMS • So, the gram is the basic or standard unit of mass in the metric system • We will use a triple beam balance to measure mass

Triple Beam Balance Pan Rider Beams located on ARM Base

Closer look at the beams w/ weights (AKA: Poise or riders) Gram/ .1 g 100 grams 10 grams

Zero in your balance • Move all the riders to zero • Use the adjustment screw/ knob to get the arm lined up with zero on base • Torque…

What does this balance read?

100 g poise is at 300 10 g poise at 70 1 g poise at 3.34

Total mass is 373.34 grams!