Metrics and Measurement It is important to know what property you are measuring and what metric label to use on your answer.

A system of measurement where ALL coversions are by 10’s Metric System A system of measurement where ALL coversions are by 10’s

Metric Prefixes- Largest unit Base units Littlest unit “King Henry’s Darling __________ Drinks Chocolate Milk

Metric Prefixes Kilo- 1000 meters, 1000liters, 1000grams Meter -base unit for length Liter -base unit for liquid volume Gram -base unit for mass Centi-1/100th of …. Milli-1/1000th of ….

Measuring Length: Metric Ruler Use the metric side only!

Measuring Length Use the metric side of the ruler only. Notice that it is marked mm, but each of the numbers measures 1cm. Remember- In metrics, everything counts in 10’s. There are 10 mm in 1 cm. Each little line on the ruler= 0.1 cm Each big line on the ruler = 1 cm

Metric ruler Metric label for measuring length is the meter. Little meters = mm....millimeter (pencil points) or cm…..centimeter (about 2 1/2 in an inch… in your knuckle) Big meter = km…kilometer (a little shorter than a mile) (the other #’s on the car’s speedometer)

Measuring Liquid Volume Defined as the amount of space an object occupies. How much space does the matter take up? Can measure volume of a liquid using a graduated cylinder (a metric measuring cup).

Measuring Liquid Volume Tool to use (to find the volume of a liquid) is a graduated cylinder. It is like a metric measuring cup. Metric label for liquid volume is milliliter or Liter. mL…milliliter (think child’s medicine cup) L…..Liter (think bottle of soda) Read the volume from eye level. Read the bottom of the meniscus (the bottom of the bubble). Before you begin to read the measurement, be sure to know the interval (what the cylinder counts by).

Graduated cylinder Remember to check the “graduations”—What does it count by? This one counts by____mL. The 100’s are labeled, but each line counts by__?

Can a graduated cylinder also be used to measure the volume of an irregularly shaped solid object? The legend tells that it was Archimedes who discovered this law of nature while meditating in his bath-tub. He there reportedly called out Eureka!  (Greek "I have found it") when he suddenly understood that the volume of an irregular object could be calculated by finding the volume of water displaced when the object was submerged in water.

Can a graduated cylinder also be used to measure the volume of an irregularly shaped object? Yes! Measure the amount of water “displaced” by the object! First measure an amount of water in a cylinder. Add the object and allow it to sink (The water level should come up). Read the new volume. Subtract to find the difference. The difference = the volume of the object

Measuring Volume of a Rectangular Prism (block or cube) Cubes, boxes,…have a length, width, and height that can be measured. Volume(of a solid cube)= length x width x height V = l x w x h If a cube measures 4 cm by 2 cm by 5 cm, the volume of the cube would be: V= 4cm x 2 cm x 5cm = 40 cm3 Cubic centimeters (cc or cm3)is the metric label for the volume of solids

Mass The amount of matter in an object It is a constant, it does NOT change when gravity changes. Measured using a triple-beam balance Measured in: mg….milligrams( think grains of salt) g…….grams (think Splenda packet) kg…...kilograms (think …????)

Weight Measurement of how gravity pulls on an object. If gravity changes, weight changes. In the ISS, no gravity means no weight.

“I like the Metric System, my weight in kg is much less than my weight in pounds.” Common metric labels for mass: mg (milligrams)…a grain of salt g (gram)….1 Splenda packet is exactly one gram kg (kilogram)….no easy way to remember, but your weight in pounds is about 2X your weight in kg

Triple-beam balance Level surface, zeroed before you begin Start with the heaviest weights first Measure to the nearest tenth

Triple-beam balance A balance measures mass in grams. Remember to zero your balance on a level surface. Always start with the heaviest weight. Move it one notch at a time, then go back one. The one gram bar in the front measures to the nearest tenth of a gram.

Review questions: A container of red powder is placed on a triple-beam balance. Together they have a mass of 256.3 g. If the container empty has a mass of 125 g, what is the mass of the red powder? _____________ answer

Answer: Together mass is 256.3 g The container alone is 125.0g Subtract them to find the mass of the red powder. 131.3g

Review question An irregularly shaped rock is placed into a graduated cylinder that contains 50 mL of water. The level of the water rises to 67 mL. What is the volume of an irregularly shaped rock? (Remember water displacement) _______________answer

Answer: The rock has volume (it takes up space in the water) and rises the level of the water. 67mL – 50mL = 17mL or 17 cm3

Review question A cubic building block has measurements of: length= 10 cm width = 2 cm height = 3 cm What is the cubic volume of the block? (Remember…V= l x w x h _______________answer

Answer: V= l x w x h V= 10cm x 2 cm x 3cm V=60 cm3 (10 x 2 x 3 = 60) (cm x cm x cm = cm3)