Metric System Scientific Measurements

In Activity

 What country developed the metric system?  What are the base units of the metric system?

Distance base unit = Mass base unit = Volume base unit =

In Activity

 What country developed the metric system? France  What are the base units of the metric system?

Distance base unit = meter Mass base unit = gram Volume base unit = liter

Kilo Kings

In Continued Magic Equivalent Ruler

Hecto Deka Base 1 g, m, l Deci Centi Have Diamonds But Diamonds Cost Milli Money

Metric System

     Developed by the French in the late 1700’s.

Based on powers of ten, so it is very easy to use.

Used by almost every country in the world, with the notable exception of the USA.

Especially used by scientists.

Abbreviated SI, which is French for Systeme International.

Metric Prefixes

  Regardless of the unit (gram, meter or liter) the entire metric system uses the same prefixes.

Common prefixes are: kilo = 1000 centi = 1/100 th milli = 1/1000 th 1 meter = 100 centimeters= 1000 millimeters

Kilo

1000 base units

Hecto

100 base units

Metric Prefixes

Deka

10 base units

Base Units

Meter Liter Gram

Deci Centi Milli

10 of these make 1 base unit 100 of these make 1 base unit 1000 of these make 1 base unit

Length

  

Length is the distance between two points.

The SI base unit for length is the meter.

We use rulers or meter sticks to find the length of objects.

Mass

    

Mass is the amount of matter that makes up an object.

A golf ball and a ping pong ball are the same size, but the golf ball has a lot more matter in it. So the golf ball will have more mass.

The SI base unit for mass is the gram .

A paper clip has a mass of about one gram.

The mass of an object will not change unless we add or subtract matter.

Measuring Mass

 

We will use a triple beam balance scale and a digital top loading scale to measure mass.

Your mass here on earth is the same as your mass on the moon. Mass is not the same as weight.

Weight

    Weight is a measure of the force of gravity on an object .

Your weight can change depending on the force of gravity. The gravity will change depending on the planet you are on.

The SI unit for weight is the Newton (N).

The English unit for weight is the pound.

Gravity

      Gravity is the force of attraction between any two objects with mass.

The force depends on two things, distance and mass.

more distance = less gravity = less weight less distance = more gravity = more weight more mass less mass = more gravity = less gravity = more weight = less weight

Weight and Mass

Jill mass weight Earth 1 gravity 30kg 300N Moon 1/6 th gravity 30kg 50N Jupiter 2.5 gravities 30kg 750N On orbit 0 gravity 30kg 0 Newtons

 Notice that Jill’s mass never changes. Her mother will not allow us to take parts off her, or add parts to her, so her mass stays the same. Jill is 30kg of little girl no matter where she goes!

Stop Here! Day 1

Volume

   

an object.

We can find the volume of box shapes = length x width x height In this case the units would be cubic centimeters (cm 3 ).

So a box 2 cm x 3 cm volume of 30 cm 3 V = L x W x H

Base Units

 

The base unit for volume is the Liter.

We measure volume with a

graduated cylinder

.

Graduated Cylinders

 

Liquids form curved, upper surfaces when poured into graduated cylinders To correctly read the volume, read the bottom of the curve called the meniscus

Liquid Volume

 

When the metric system was created, they decided that 1 cm 3 of water would equal 1 milliliter of water and the 1 mL of water will have a mass of one gram.

1cm 3 water =1 ml of water = 1 gram

Water Displacement

 

We can use water displacement to find the volume of objects that are not box shaped.

We can put water in a graduated cylinder. If a rock causes the level to rise from 7 to 9 ml, the rock must have a volume of 2-mL.

Water Mass and Volume

    

1 cm 3 of water = 1 mL of water = 1 gram

So what would be the mass of 50 mL of water?

50 grams

So what would the mass of 1 liter of water be?

1 L = 1000 mL so its mass would be 1000 grams or a kilogram.

Density

 

Density is the amount of matter compared to the amount of space (mass) (volume) the object occupies.

We will measure mass in grams and volume in ml or cm 3

Density Formula

   

Density is mass divided by volume.

Density = mass/volume Remember, all fractions are division problems. Since the unit for mass is grams, and the unit for volume is ml or cm 3 , then the

unit for density is g/ml, or g/ cm

3

Density Formula Wheel

  

Formula wheels make it easy to solve density problems.

Cover the property you are trying to find, and do what is left over.

To find density, cover the word density. You have mass over volume remaining. So divide mass by volume to find density!

Mass density volume

Density Formula Wheel

 

To find mass, you cover the word mass. You now have mass times volume remaining.

To find volume, cover volume. You have mass over density remaining, so divide mass by

density to find volume.

Mass density volume

Understanding Density

     In the following illustrations, each will 3 Each g will represent 1 gram.

Mass = 24g Volume = 8 cm 3 Density = 3g/cm 3 g g g g g g g g g g g g g g g g g g g g g g g g

g g g g g g g g g g g g g g g g g g g g g g g g •In other words, there are 3 grams in every cm 3 .

g g g g

Density Problem 2

g g g g g g g g •Mass = 12 grams •Volume = 6 cm 3 •Density = 2 g/cm 3 • In English we say the density of the object is 2 grams in every cubic centimeter.

Density Problem 3

g g g g g g g g g g g g g

•Our previous problems were materials of uniform density. They were the same stuff throughout. But many materials are not. Gravel is a great example.

•Mass = 16 grams •Volume = 8 mL •Density = 2 g/mL

Water and Density

  

Since 1-gram of water has a volume of 1-mL, then the density of water will always be 1 gram/ml.

5o-mL of water will have a mass of 50 grams, so again the density of pure water will be 1 g/ml.

A kg of water will have a volume of 1000-mL, so it’s density will be 1 gram/ml.

  

Floating and Sinking

Less dense materials will float on top of more dense materials.

Objects with a density of less than 1-g/mL will float on top of water.

Objects with a density greater than 1 g/mL will sink in water.

Neutral Buoyancy

  Objects with a density equal to the density of water will float in mid water, at what ever level you place the object.

Fish and submarines control their depth by changing their density.

Objects that Sink!



Objects with a density greater than 1 g/mL will sink in water.

Titanic Sails the Ocean Blue

    

on its maiden voyage.

What is the density of this enormous, steel hulled ship, full of machinery, coal, people, and all sorts of It’s floating, so it’s density must be less than 1 g/mL.

How can this be?

Titanic verses Iceberg

   

After HMS Titanic struck the iceberg, she started to fill with water.

What happened to her density?

As she took on more and more water , her density got closer and closer to 1 g/mL.

The denser the ship became, the lower she settled into the water.

Wreck of the Titanic

 

What is the density of the Titanic resting on the ocean floor?

Must be greater than 1 g/mL, as her steel hull is full of water instead of air.

Comparing Densities

•Where is

the most dense object?

•Where is

the least dense object?

Density Review

    We don’t actually count g’s to find the mass of objects. How would you find the mass of a rock?

Use a balance scale.

In real life, how would you find the volume of a rock?

Use a graduated cylinder and see how much water the rock displaces .

Out Practice Activity

 What is the mass of 50 ml of water _______?

 What is the volume of 50 ml of water _______?

 What is the density of 50 ml of water _______?

 What is the mass of the carriage bolt_______?

 What is the volume of the carriage bolt ______?

 What is the density of the carriage bolt ______?