# ra llil Introduction to the Metric System ite

• Slides: 39

ra llil Introduction to the Metric System ite r Symbols Prefixes Converting Within the Metric System og kil mi m e te r m r e t e Kilom gram

Metric System Usain Bolt won the gold medal in the 100 meter men’s track final of the 2008 Olympic games held in Beijing, China. Dawn Harper won the gold medal in the 100 meter women’s hurdle’s final at those same Olympic games.

Metric System But how far is 100 meters? How far is 10 meters? What about 10 feet? Can you easily figure out how far 10 feet is, but have trouble knowing how far 10 meters is?

Metric System You are not alone! Measuring in metrics is something we are not used to doing. In the United States, we use the English system of measurement: pounds, feet, inches, miles, gallon, pint, etc.

Metric System However, scientists around the world use the International System of Measurements, (SI) or Metrics, to measure distances, volumes, masses, and temperatures. In fact, most countries use the SI system of measurement. The countries in red are NOT using the metric system as a standard measurement system.

Metric System If you travel to France, the distances and speeds marked on the road signs will be in kilometers, not in miles. You would buy milk measured in liters

Metric System You may be used to buying water and soda in liters, so you are already using the metric system!

Metric System Use your index finger to measure the width of your desk. How many fingers wide is it? Ask a classmate how many fingers wide their desk is.

Metric System Do all of the desks in your classroom look like they are the same width? Did everyone arrive at the same or different answers? What would the world be like if we all used our index fingers to measure length? Why do you think it is important to have a standard system of measurement?

Metric System Try converting 18 inches into feet. How about 14 ounces into pounds? Ok, how many ounces in a pound again? The English system is not easy to use.

Metric System Scientists need a standard system of measurement that is easy to use and convert measurements. Fingers will not do! The English system is confusing! Using the same measuring system by everyone world-wide allows for uniformity of measurements.

Metric System The metric system is based on the number 10. It is easy to use because each measurement can be converted by simply multiplying or dividing by a factor of 10.

Metric System Look at the chart below to see the basic metric units and their symbols. Measurement Unit Symbol Length meter m Mass gram g Volume liter L Temperature Kelvin (or Celsius) K (C)

Metric System Meter, Liter, and Gram are all base units. Prefixes are used with the base unit of measurement and indicate which multiple of 10 is being used. Kilo- 1000 Milli- 1/1000 Centi- 1/100 Kilometer, milliliter, and centigram are examples of metric units that use prefixes.

Metric System Here are some commonly used prefixes in the metric system. Notice the multiplying factors are all based on the number 10. Prefix Symbol Multiplying Factor Giga Mega Kilo Hecta Deka Deci Centi Milli Micro Nano G M k h da d c m u n 1, 000, 000 1, 000 1000 10 0. 1 0. 001 0. 000000001

Metric System The basic unit of length is meter. A meter is about the length of a yard in the English system. The length of a room or the length of a hallway would be measured in meters. A centimeter is one-hundredth (1/100) of a meter. The length of your finger or your pencil would be measured in centimeters.

Metric System Use a metric ruler or a meter stick to measure length in the Metric System.

Metric System The basic unit of mass is kilogram. A kilogram is about 2. 2 pounds. The mass of one of your large textbooks may be about 1 kilogram. A gram is one-thousandth of a kilogram. Pencils, candies, and cereal can be measured in grams.

Metric System Use a balance or scale to measure mass in the Metric System.

Metric System The basic unit of volume is the Liter. A liter is about 34 ounces, or about 1/4 of a gallon. The volume of a large bottle of soda is 2 liters. A milliliter is one-thousandth (1/1000) of a liter. A glass of water, a bottle of drinking water, and a jar of spagetti sauce can be measured in milliliters.

Metric System Use a graduated cylinder to measure volume in the Metric System.

Metric System One of two units may be used in the Metric System when measuring temperature. 0 degrees Celsius = freezing point of water 0 degrees Celsius = 273 Kelvin 37 degrees Celsius = body temperature 310 Kelvin = body temperature

Metric System Once you learn how to measure in the Metric System, you will need to convert from one unit to another on occasion. For instance, you may have a balance that measures in grams, but your lab directions call for you to record the mass in kilograms. You will need to know how to convert the units.

Metric System An easy way to convert between the commonly used measurements is to simply move the decimal. But… How many places do you move the decimal? Which direction do you move it? Here’s an easy method to converting measurements within the Metric System which uses a mnemonics chart.

Kilo- Hecta- Deka- Base – Deci- Centi- Milli- No pref ix Metric System 1000 10 1 1/1000 Here are some prefixes and their corresponding values. Reading from left to right: each prefix is 10 times smaller than the value on its left. Reading from right to left: each prefix is 10 times larger than the value on its right.

1 Milli- 10 Centi- Deka- 100 Deci- Hecta- 1000 Base – No pref ix meter Kilo- Metric System 1/1000 A kilometer is 10 times longer than a Hectameter. A kilometer is 1000 times longer than a meter

D King Henry Died Milli- H Centi- K Deci- 10 1000 Base – Deka- 100 Kilo- Hecta- No pref ix Metric System 1 1/1000 D C M B By Drinking Chocolate Milk A mnemonic can help you with conversions within the Metric System. Each letter of the mnemonic begins with the first letter of the metric prefix.

1 King Henry Died By Drinking Milli- 10 Centi- Base – 100 Deci- Deka- 1000 Kilo- Hecta- No pref ix Metric System Memo rize the mnem onic! 1/1000 Chocolate Milk You will always be able to rebuild this chart if you memorize the mnemonic!

Metric System Since the Metric System is based on factors of 10, we need only worry about moving the decimal when converting between metric measurements. Let’s try a conversion: How many milliliters are in 1. 25 Liters? OR 1. 25 L = ? m. L

1 King Henry Died By Drinking Milli- 10 Centi- Base – 100 Deci- Deka- 1000 Kilo- Hecta- No pref ix Metric System 1/1000 Chocolate Milk Start with the mnemonic: King Henry Died By Drinking Chocolate Milk. Now add the prefixes that start with the first letter of the mnemonic. They will be in the correct order!

1 Henry Died By Drinking Milli- 10 Centi- 100 Deci- Base – King Deka- 1000 Hecta- Kilo- No pref ix Metric System Each Prefix along the chart is a “Place” or “Spot”. 1/1000 Chocolate Milk Now we are ready to make the conversion: 1. 25 L = ? m. L Step 1: Since Liter has no prefix, we will place our pencil on the “Base-No Prefix” spot. Step 2: Find “Milli-” on the chart.

ix Drinking Chocolate Milli- By Centi- Died Deci- No pref Base – Henry Deka- King Hecta- Kilo- Metric System Milk Step 3: Start at “Base-No Prefix” and jump your pencil to the right towards “Milli-”. You moved 3 places to the right to arrive at “Milli”. Step 4: Now move the decimal in 1. 25 L to the right 3 places. This matches what you just did on the chart.

Metric System 1. 250 Move the decimal to the right 3 places. Add a zero in the last place. 1. 25 L = 1250 m. L You need not keep the decimal visible – it is understood to be to the right of 1250 ml.

ix Base – Deci- Centi- Milli- No pref Deka- 1000 Hecta- Kilo- Metric System 100 10 1 1/1000 Try another conversion: 247 meters = ? kilometers Follow the previous steps: Place your pencil on “Base-No Prefix” and move to “Kilometers” by jumping 3 spaces to the left.

Metric System Now move the decimal point 3 spaces to the left. 247 m Add a zero in front of the decimal. The decimal is understood to be to the right of ‘ 7’. 247 m = 0. 247 km Remember: Meter – m, kilometer – km

King Henry ix Convert 56. 2 cm to mm. By Drinking Chocolate Milli- Centi- Deci- No pref Died Base – Deka- Hecta- Kilo- Metric System Milk Move the decimal one place to the right. 56. 2 cm = 562 mm

Base – Died By Drinking Chocolate Convert 467. 0 centigrams to grams You see that the decimal needs to move to the left two places. 467. 0 cg = 4. 670 g Milli- Deka- Henry Centi- Hecta- King Deci- Kilo- No pref ix Metric System Milk

1 King Henry Died By Milli- 10 Centi- Base – 100 Deci- Deka- 1000 Kilo- Hecta- No pref ix Metric System 1/1000 Chocolate Milk Drinking Draw the above chart on your paper and try these conversions: 1. 93. 2 m. L = ? L 2. 845. 34 g = ? Kg 3. 0. 56 m = ? cm Answers are revealed on the next slide.

King ix Base – Deci- Centi- Milli- No pref Deka- 1000 Hecta- Kilo- Metric System 100 10 1 1/1000 Henry Died Answers: 1. 93. 2 m. L = 0. 0932 L 2. 845. 34 g = 0. 84534 Kg 3. 0. 56 m = 56 cm By Drinking Chocolate Milk Remember to add zeroes as placeholders where necessary.