Unit II: Measurement Unit II: Measurement of Matterof Matter

Metric System:

•A system of measurement based on the number 10

Parts of the Metric SystemParts of the Metric System LengthLength MassMass VolumeVolume DensityDensity

WHY DO WE USE THE METRIC WHY DO WE USE THE METRIC SYSTEM?SYSTEM?

•Almost all other countries are using the metric system•Other countries’ companies are refusing to buy products from the U.S. if not labeled in metric units•Scientists need a universal way to communicate data (SI Units)

Length: distance between two points

MeterMeter: : about the length of a yard—length of your about the length of a yard—length of your

leg (m)leg (m) CentimeterCentimeter: :

about the width of your pinky finger (cm)about the width of your pinky finger (cm) MillimeterMillimeter: :

about the thickness of a dime (mm)about the thickness of a dime (mm) KilometerKilometer: :

a little less than mile (km)a little less than mile (km)

The longer lines on the The longer lines on the metric ruler are calledmetric ruler are called……

centimeterscentimeters

The shorter lines on the The shorter lines on the metric ruler are calledmetric ruler are called……

millimetersmillimeters

There are……There are……

10 millimeters in 1 centimeter10 millimeters in 1 centimeter 100 centimeters in 1 meter100 centimeters in 1 meter 1,000 millimeters in 1 meter1,000 millimeters in 1 meter 1,000 meters in 1 kilometer1,000 meters in 1 kilometer

10.5 cm10.5 cm

105 mm105 mm

Measure the turtle from the rear of its shell to the tip of its nose. Record its length in both centimeters and millimeters.

Measure the Lines in cm Measure the Lines in cm & mm& mm

To Earn Extra Credit, make….

Chocolate Chip Cookies! 2 ¼ Flour1 Baking Soda1 Salt2 Butter¾ Sugar1 Vanilla2 Eggs2 Chocolate Chips

What’s the point…….

Don’t forget UNITS or no one will understand what you mean!!!

When writing When writing numbers…..numbers…..

They must be written to the nearest They must be written to the nearest 1010thth and the correct units!!!! and the correct units!!!!

Length = 10Length = 10

Written as 10.0 cmWritten as 10.0 cm

Length = 10.3Length = 10.3

Written as 10.3 cmWritten as 10.3 cm

Mass: the amount of matter (“stuff”) an object contains

**MASS DOES NOT CHANGE AS YOU MOVE FROM PLACE TO PLACE—it only changes if you get bigger or smaller!

•Gram: about 1 M & M (g)•Kilogram: about 2 pounds (kg)

**there are 1,000 grams in a Kilogram

Mass LabMass Lab

Name of ItemName of Item MassMass

Unsharpened PencilUnsharpened Pencil   

Blue Calculator with CoverBlue Calculator with Cover   

Glue StickGlue Stick   

Chem PlateChem Plate   

AgendaAgenda   

Safety GlassesSafety Glasses   

Rubber StopperRubber Stopper   

GPS UnitGPS Unit   

BeakerBeaker

ScissorsScissors   

WeightWeight: measure of pull of gravity of : measure of pull of gravity of an object.an object.

**THIS WILL CHANGE AS GRAVITY **THIS WILL CHANGE AS GRAVITY CHANGES!CHANGES!

Pounds (lbs)Pounds (lbs) **the bigger the planet, the bigger the **the bigger the planet, the bigger the

gravitational pull = more weightgravitational pull = more weight

How much do you How much do you weigh…..weigh…..

VolumeVolume: amount of space an object takes : amount of space an object takes upup

Regularly Shaped SolidsRegularly Shaped Solids (square / (square / rectangle)rectangle)

Length x Width x HeightLength x Width x Height (cm (cm33))

Liquid: Liquid: Liters (l)Liters (l) Milliliters (mL)Milliliters (mL)

What is used to measure What is used to measure liquid volumeliquid volume……

Graduated Graduated cylinder.cylinder.

Goes up by 1 mL

Meniscus (curve—read bottom!)

What is density?What is density?

DensityDensity: how much “stuff” (mass) is : how much “stuff” (mass) is in a certain volume (amount of space)in a certain volume (amount of space)

……but what does that mean???but what does that mean???

All matter is made up of tiny All matter is made up of tiny particles moving around—the particles moving around—the more particles, the more massmore particles, the more mass

When you measure When you measure densitydensity, you are , you are measuring how many tiny particles measuring how many tiny particles are in a given spaceare in a given space

Density = Density = MassMass

VolumeVolume

Density Units: g/cmDensity Units: g/cm33 or or g/mLg/mL

How does the density of an How does the density of an object determine if it will object determine if it will float or sink?float or sink? Objects with LESS DENSITY float in Objects with LESS DENSITY float in

things that have greater densitythings that have greater density The density of water 1.0 g/mL—The density of water 1.0 g/mL—

meaning any object with a density meaning any object with a density GREATER than 1.0 g/mL will SINK!GREATER than 1.0 g/mL will SINK!

>1.1 g/mL1.0 g/mL.9 g/mL.5 g/mL

.1 g/mL

DENSITY DOES NOT DENSITY DOES NOT CHANGE IF YOU CUT AN CHANGE IF YOU CUT AN

OBJECT IN HALF!!OBJECT IN HALF!!

Why do Hot Air Balloons Why do Hot Air Balloons Float?Float?

Because hot air is less dense than Because hot air is less dense than cold air……..cold air……..

But why???But why???

It has to do with the It has to do with the Kinetic Theory Kinetic Theory of Matterof Matter: all matter (stuff) is : all matter (stuff) is composed of tiny particles in motion.composed of tiny particles in motion.

PhasePhase Position of ParticlesPosition of Particles Particle Particle MotionMotion PicturePicture

SolidSolidClose together with a Close together with a

definite shape and definite shape and volumevolume

SlowSlow   

LiquidLiquid

More spread out More spread out without a definite without a definite

shape but a definite shape but a definite volumevolume

MediumMedium   

GasGasVery far apart with Very far apart with no definite shape or no definite shape or

volumevolumeFastFast   

So…Why do Hot Air So…Why do Hot Air Balloons Float?Balloons Float?

When air is heated, the particles When air is heated, the particles move faster and move faster and spread outspread out—making —making less “stuff” in the same amount of less “stuff” in the same amount of space.space.

Less Density!Less Density!