IT IS IMPORTANT THAT SCIENTISTS CAN COMMUNICATE WITH EACH OTHER.

Measurements

Measurement: comparison of some aspect (dimensions, quantity, capacity) of an objector phenomenon with a standard unit.

The standard makes the measurement valid.

All measurements need a number and unit for comparison.

Use prefixes in measurements:

kilo = 1000 hecto = 100 deka = 10

deci = 1/10 centi = 1/100 milli = 1/1000

Scientists use metric units to measure length, volume, mass, weight, density, and temperature

It is easier to convert meters to centimeters or millimeters than to go from yards to feet or inches. All you have to do with the metric system is move decimal places.

Precision: gives a better representation of the value.

2.1cm is more precise it is measured to the nearest tenth of a cm

2cm is only measured to the nearest cm

Length

Metric standard for length is the meter (m)

1 m = 100 cm = 1000 mm (1) m (1/100) m (1/1000) m

Whereas: 1000m = 1 km

What if you wanted to measure something the size of an atom?

Angstrom = one ten billionth of a meter

Sometimes we are given a unit that we don’t want; we need to use a conversion to get the unit we want.

For example: Given 5m want the measurement in cm

We know that 100cm = 1 m Therefore we can set up a conversion

5m x 100cm/1m = 500cm

More Conversions: using decimals

2km = m

5mm = m

6.3m = cm