Notes – Measurement (8 th grade). International System of Units a way of measuring based on...

Notes –Measurement(8th grade)

International System of Units

• a way of measuring based on multiples of ten (10, 100, 1000…)

• abbreviated S.I.• also called the metric system

• most of the world uses it

Length

• the distance between two points

• the basic unit: meter

• tool used: ruler or meterstick NO!

YES!

Length

Length

Know what each line represents!

2.0

2.1

2.2 2.4 2.6 2.8 3.0

2.3 2.5 2.7 2.9

Length

1. Length = ______ _____

Length

2. Length = ______ _____

Length

3. Length = ______ _____

Length

4. Length = ______ _____

Length

1. Length = ______ _____1.9 cm

Length

2. Length = ______ _____4.3 cm

Length

3. Length = ______ _____16 cm

Length

4. Length = ______ _____5.8 cm

Volume

• the amount of space an object takes up

• the basic unit: depends if it’s solid or liquid

• tool used: depends if it’s solid or liquid

Liquid Volume

• the basic unit: liter

• tool used: graduated cylinder

Liquid Volume

• liquids curve inside a narrow container

• a meniscus is the convex or concave surface of a column of liquid

How do you measure?

or

Liquid Volume

1.Figure out the scale being used by interpreting what each unlabeled line is.

6.0

8.0

6.16.26.36.4

6.56.66.76.86.9

7.0 ?

NOPE!

Liquid Volume

1.Figure out the scale being used by interpreting what each unlabeled line is.

6.0

8.0

6.26.46.66.8

7.07.27.47.67.8

YEP!

Liquid Volume

2. Line your eye up with the water line.

Liquid Volume

3. Pick the line closest to the bottom of the curve.

Liquid Volume

Which line?

or

Volume = ___________

6.6 mL

Solid Volume

• the basic unit: cubic meter

• tool used: ruler or meterstick

Solid Volume

• area = length x width

• the unit is squared

6 square meters 6 m2

meters

meters

Solid Volume

• volume = length x width x height

• the unit is cubed

What is the volume?

4 cm x 3 cm x 2 cm

24 cm3

Mass

• the amount of matter in an object

• the basic unit: gram

• tool used: triple beam balance or electronic balance

• Triple-Beam Balance Use:1. Move sliders until it balances.

2. Add together the numbers on all 3 sliders.

Mass

Mass100 g 60 g+ 7.5 g167.5 g

What is the mass?

• To find the mass of ONLY the sand:1. Find the mass of the empty cup.

2. Find the mass of the sand and the cup.

3. Subtract.

Mass

Mass167.5 g- 45 g122.5 gIf the mass of the cup

is 45 g, what is the mass of only the sand?

Mass

• to find the mass of ONLY the sand:1. Place the EMPTY beaker on the balance.

2. Press the “tare” or “zero” button to get the mass to zero.

3. Fill the container with what you want to weigh, and record the mass.

Temperature

• the measure of the average energy of the motion of particles in a substance

• the basic unit: º Celsius

• tool used: thermometer

• water freezes at 0ºC and boils at 100ºC.

• put a minus sign (-) if it’s below zero

Temperature

SCALEeach line is

__ degree(s)

SCALEeach line is

__ degree(s)

SCALEeach line is

__ degree(s)

1 1 2

Distance in Space

• astronomical unit - the average distance from Earth to the sun (about 150 million km)

• Use astronomcal units (AU) to measure distances within our solar system (planet to planet)

Distance in Space

• light-year - the distance light travels in one year (about 10 trillion km)

• Use light-years to measure distances outside our solar system (galaxy to galaxy, star to star)

SummarizeUnit Lab Tool

Length

Liquid Volume

Solid Volume

Mass

Temperature

meter (m)ruler or

meterstick

liter (L)graduated

cylinder

cubic meter (m3) ruler

gram (g)triple beam balanceor electronic balance

°Celsius (°C) thermometer