Measurement – A Common Language

The Metric System The metric system is a decimal system

of weights and measures. It is based on the unit of length called

the METER. The metric system is now called, The

International System of Measurement (SI for short).

To get the meter, they divided a line from the north pole to the equator into 10 million parts!

Why do we use Metric System

No numbers to memorize

Easy to say and write

Converts by multiples of 10

Used all around the world

Units of Measurement

Prefixes: Kilo = 1000 Hecto = 100 Deca = 10 (Base Unit)= 1 Deci = .1 Centi = .01 Milli = .001

Examples: Kilometer Hectometer Decameter (Meter) Decimeter Centimeter Millimeter

Length:

The standard unit of length in the metric system is the meter.

Common length units:1 millimeter = 1 mm1 centimeter = 1 cm1 meter = 1 m1 kilometer = 1km

Let’s look at the meter:

1 meter is a little longer than 1 yard or 3 feet.

There are 10 decimeters in 1 meter There are 10 centimeters in 1

decimeter. There are 10 millimeters in 1 centimeterMeasuring length – p. 48

The shell of the turtle in figure 2 is 8.8 cms, how many mms is this?

English to Metric Conversions

39,370 inches = 1 kilometer

3280.8 feet = 1 kilometer

.62 miles = 1 kilometer

1 inch = 2.54 cm

1 foot = 30.48 cm

1 yard = .914 m

1 mile = 1609.3 m

1 mile = 1.609 km

****You do not need to know these.

Let’s Practice

Use the meter stick or the metric ruler to measure the following: careful when choosing what unit to measure in…

1. the length of your lab table2. the length of your science textbook3. the length of your partners hand4. the length of your own pinky finger5. the width of your pinky finger nail6. the width of your pencil point

MassMass is a measure of how much matter an object contains.

The basic unit for mass is kilogram. How many grams = 1 kg?

In the science lab, we will measure in grams.

But…. what is a gram?

The difference between MASS and WEIGHT

Weight = the force of gravity on an object.

Mass = the amount of matter an object contains

120lbs on Earth = 20lbs on the moon

50 kgs on Earth = 50 kgs on the moon

Triple Beam Balance – a device for measuring mass in grams.

Measuring Mass

Let’s learn the parts of the triple beam balance and practice measuring mass. Desktop text p. 49

TIME

The SECOND is the standard SI unit used to measure time.

There are 60 seconds in 1 minute.

There are 60 minutes in 1 hour.

Measuring Volume

Volume - the amount of space an object takes up. **The standard unit for volume is the liter•Volume of liquid = pour liquid into

graduated cylinder and measure amount

•Volume of regular shaped solids = length x width x height in cms (cm3)

•Volume of irregular shaped solids (like a rock)= water displacement.

DENSITY

Density = mass unit = g/cm3 volume = g/ml

p. 52 Let‘s READ.

p.53 Densities of common substances. Once you know an objects density, you can determine whether or not the object will float in a given liquid.

Look at the chart, what is the density of water? Will Aluminum sink or float in water? Explain how you know

What is the density of a pencil with a volume of 4ml, and a mass of 24g?

What is the density of an object with a volume of 12cm3, and a mass of 36g?Let’s find the Mass and Volume of our two

wooden cubes…

The density of water is 1g/cm3 or 1g/ml (1ml = 1cm3)