The Metric System September 4, 2008

What does the word measure mean? How do you measure things? What are some things that you can measure? Everyone take your ruler and measure something around you…… What measurement did you come up with? What side of the ruler did you use?

Different measurements use different units. What is a unit? A unit is the amount used to measure something.

Units in the US Here in the US, we use the English system…. Can you name some units that we use? Liquid ______________________ Mass ______________________ Length ______________________ Temperature __________________ Time ________________________

The System Everyone Else Uses… In science class, we use the Metric System, or the Systeme International (SI). The metric system is a system of measurement that is used by scientists all over the world. Most countries only use the metric system.

Metric Units In the metric system, we use the following terms: Grams, Liters, Meters, Seconds, and Celsius. Can you guess which one is used for: Liquid ______________________ Mass ______________________ Length ______________________ Temperature __________________ Time ________________________

Metric Units Measurements: Length Mass Volume Time Metric Units: English Units: Meter (m) Inches/ Feet Gram (g) Pounds Liter (L) Gallon/ Ounce Seconds (s) Minutes

The metric and SI systems are based on units of 10. Each unit is 10 times greater then the unit before it (x10) 1 x 10 = 10 10 X 10 = 100 10 x 100 = 1,000

Prefixes To show a change in the size of a unit, you add a prefix to the unit. Prefixes and their meanings: Kilo- is 1,000 Hecto- is 100 Deca- is 10 Deci- is 1/10 Centi- is 1/100 Milli- is 1/1000

I like to remember King Henry

King Henry Died Unexpectedly Drinking Chocolate Milk The pneumonic: King Henry Died Unexpectedly Drinking Chocolate Milk Memorize this!

To convert within the metric system: Draw a line and add 7 tick marks. Now we’ll add the units. To convert, simply move from the unit you have to the unit you want, and move the decimal point that many spaces.

Let’s practice a few conversions Part A: Conversions 1000 mg = _______ g 1 L = _______ mL 160 cm = _______ mm 14 km = _______ m

Units of Length Length is the distance from 1 point to another. In the metric system, the basic unit of length is the meter. Example: 1,000 millimeters = 1 meter On your ruler, 1 centimeter = 10 millimeters

Units of Volume What is volume? Volume is the amount of space an object takes up. You can measure the volume of liquids and solids. Solid volume = cubic centimeters. Liquid volume = Liters. What are some things you can measure the volume of?

How do we measure the volume of a solid? 1 cubic centimeter (cm³) = 1 milliliter V= L x W x H. To find volume, use your ruler to measure the length, width, and height of the object. Multiply them to get cubic cm (or cm³)

Example: V = L x W x H V = 10cm x 5cm x 4cm V= 200 cm³

How do we measure volume? We use a graduated cylinder to measure liquid volume. Each mark, or interval, is 1 milliliter.

To read a measurement in a graduated cylinder: Pour some water into a graduated cylinder Set it on a flat surface (your table) Get low enough to look at it from eye level. What do you see?

Does the water look u-shaped? This is called a meniscus. A meniscus is the curve at the surface of a liquid. To measure this, you read the mark on the graduated cylinder closest to the bottom of the meniscus.

Mass Mass is the amount of matter an object contains. Causes an object to have weight in a gravitational field. The unit used for mass is grams. How do we measure mass? Spring Scale Triple Beam Balance Electronic Balance

Temperature Temperature is the degree of hotness or coldness of a body or environment. In science, we measure temperature in degrees Celsius (0C). To convert between 0F and 0C: 0C= 5(0F-32)/9 0F= 9x 0C +32/5

Now, work on your Estimation and Measurement Lab QUESTIONS: 1. Which measurement were you the most accurate at? 2. Which measurement were you the least accurate at? 3. Why were you better at estimating at some dimensions than others? 4. List three ways estimating can be used to help you in everyday life. 5. How could you improve your estimating skills?  6. Why is estimation not a good skill to depend on in a science lab?

Any questions…..