1-4 Tools & Procedures Metric System Scientific Measurements

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, the entire metric system uses the same prefixes.

Metric Prefixes Order from largest to smallest Kilo = 103 or 1000 units Hecto = 102 or 100 units Deka = 10 1 or 10 units Base Unit = meter or liter or gram Deci= 10-1 or .1 units Centi = 10-2 or .01 units Milli = 10-3 or .001 units Hint: Kittens Have Dark Mittens During Cold Months

Metric abbreviations Kilo = k and base unit for example Kilometer = km Hectometer = hm Decigram = dg Milliliter = ml

Metric Conversion To convert to a larger unit move the decimal point to the left or divide Ex. 1 meter to _____ killometers 1.0m moving left three units so .001 kilometers To convert to a smaller unit, move decimal point to the right or multiply Ex. 1 Liter to milliliters 1.0 L moving three units to the right 1000 mL

How many jumps does it take? Ladder Method 1 2 3 KILO 1000 Units HECTO 100 Units DEKA 10 Units DECI 0.1 Unit Meters Liters Grams CENTI 0.01 Unit MILLI 0.001 Unit How do you use the “ladder” method? 1st – Determine your starting point. 2nd – Count the “jumps” to your ending point. 3rd – Move the decimal the same number of jumps in the same direction. 4 km = _________ m Starting Point Ending Point How many jumps does it take? 4. 1 __. 2 __. 3 __. = 4000 m

Try these conversions using the ladder method. Conversion Practice Try these conversions using the ladder method. 1000 mg = _______ g 1 L = _______ mL 160 cm = _______ mm 14 km = _______ m 109 g = _______ kg 250 m = _______ km Compare using <, >, or =. 56 cm 6 m 7 g 698 mg

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 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 from it.

Measuring Mass We will use a triple beam balance scale to measure mass. Gravity pulls equally on both sides of a balance scale, so you will get the same mass no matter what planet you are on.

Volume Volume is the amount of space contained in an object. We can find the volume of box shapes by the formula Volume = length x width x height In this case the units would be cubic centimeters (cm3). So a box 2 cm x 3 cm x 5cm would have a volume of 30 cm3 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 cm3 of water would equal 1 milliliter of water and the 1 mL of water will have a mass of one gram. 1cm3 water =1 ml of water = 1 gram

Water Mass and Volume 1 cm3 water = 1 mL of water = 1 gram So what would be the mass of 50 mL of water be? 50 grams So what would be the mass of 1 liter of water be? 1 L = 1000 mL so its mass would be 1000 grams or a kilogram.

Metric Conversion Challenge Write the correct abbreviation for each metric unit. 1) Kilogram _____ 4) Milliliter _____ 7) Kilometer _____ 2) Meter _____ 5) Millimeter _____ 8) Centimeter _____ 3) Gram _____ 6) Liter _____ 9) Milligram _____ Try these conversions, using the ladder method. 10) 2000 mg = _______ g 15) 5 L = _______ mL 20) 16 cm = _______ mm 11) 104 km = _______ m 16) 198 g = _______ kg 21) 2500 m = _______ km 12) 480 cm = _____ m 17) 75 mL = _____ L 22) 65 g = _____ mg 13) 5.6 kg = _____ g 18) 50 cm = _____ m 23) 6.3 cm = _____ mm 14) 8 mm = _____ cm 19) 5.6 m = _____ cm 24) 120 mg = _____ g

Compare using <, >, or =. 25) 63 cm 6 m 27) 5 g 508 mg 29) 1,500 mL 1.5 L 26) 536 cm 53.6 dm 28) 43 mg 5 g 30) 3.6 m 36 cm

Journal 9/26/10 Describe how to make conversions in the metric system. 1. From a larger to smaller unit 2. From a smaller to larger unit You may use diagrams to help explain your response

Water Displacement We can use water displacement to find the volume of objects that are not boxed shaped. We can put water in a graduated cylinder. If a rock causes the level to rise from 7 to 9 ml, the the rock must have a volume of 2-mL.

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.

Temperature 0 degrees Celsius = freezing point of water 100 degrees Celsius = boiling point of water

Gravity Gravity is the force of attraction between any two objects with mass. The force depends on two things: more distance = less gravity = less weight less distance = more gravity = more weight more mass = more gravity = more weight less mass = less gravity = less weight

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

Density Density is the amount of matter (mass) compared to the amount of space (volume) the object occupies. We will measure mass in grams and volume in ml or cm3

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 cm3, then the unit for density is g/ml, or g/ cm3

Density Formula Wheel Mass 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 Mass 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 represent 1 cm3. Each g will represent 1 gram. Mass = 24g Volume = 8 cm3 Density = 3g/cm3 g g g

In other words, there are 3 grams in every cm3. g g g

Density Problem 2 g g Mass = 12 grams Volume = 6 cm3 Density = 2 g/cm3 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 The Titanic is sailing on its maiden voyage. What is the density of this enormous, steel hulled ship, full of machinery, coal, people, and all sorts of heavy things? It’s floating, so it’s density must be less than 1 g/mL. How can this be? The Titanic is a hollow vessel full of air!

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.