Slide 1: Making Measurements & Using the METRIC SYSTEM Physical Science 200 p.204-205
Slide 2: Types of OBSERVATIONS Quantitative: Tells us how many. Describes “Quantity” Describes observations with numbers. Qualitative: Tells us about it. Describes “Quality” Describes observations with words.
Slide 3: Qualitative Vs. Quantitative His shirt is red. There are 2 apples left. The table is 5 meters long. A blue crystal formed on the bottom of our 100mL beaker. Her shirt is 100% cotton.
Slide 4: What are units? Steve has 10. There are 43.6 of salt. Numbers do not make sense if there is no unit. A unit tells us what the number measures. In science class there are NO NAKED NUMBERS- make them appropriate with a unit!
Slide 5: Precision Vs. Accuracy Precision is how closely repeated measurements match each other. If you can measure something 1000 times and every time you get the same measurement, you are precise. Accuracy is how closely a measurement matches the correct or expected value. If you measure something very closely to the measurement that it is supposed to be, you are accurate. A ball player's height can be measured precisely, but still not be accurate.
Slide 6: How tall is that horse? In the past it was common to measure the height of a horse in hands. Measure the height of your desk in hands and write it below: Is this a good system for measuring?
Slide 7: The International System of Units ALL SCIENTISTS us the International System of Units. We abbreviate it as SI. Some good things about measuring in SI: It is based on multiples of 10. There are no fractions- we use decimals in the metric system. All scientists use the International System of Units.
Slide 8: Who uses the SI system? In everyday life, just about everyone except for US! These countries do not use the metric system: The United States of America Liberia Myanmar ALL SCIENTISTS IN THE WORLD USE THE SI SYSTEM OF MEASUREMENT!
Slide 9: What are prefixes? Pre means “before” A prefix is a small part of a word that comes before the word. Metric prefixes equal a number.
Slide 10: Common Metric Prefixes Prefix Symbol Meaning Giga- G 1 000 000 000 or 109 Mega- M 1 000 000 or 106 kilo- k 1000 hecto- h 100 deka- da 10 deci- d 0.1 (one tenth) centi- c 0.01 (one hundredth) milli- m 0.001 (one thousandth) nano- n 0.000 000 001 or 10-9
Slide 12: How can you put those numbers in your calculator? Try these: 104 10-4 10-2 102 103
Slide 13: Adding prefixes When we measure, we can add a prefix to change the value. 1 nanosecond = how many seconds? Find nano- on your chart. What does it mean? 1 nanosecond = 10-9 seconds 1 kilometer = 1000 meters 1 milligram = 0.001 grams
Slide 14: Rules for writing metric symbols Do not use a period. 7s [not 7sec.]  Leave a space. 6 kg [not 6kg]  Do not add an s to the symbol. 10 Kilometers = 10 km [not 10 kms]  Do not capitalize, unless it is supposed to be capital. Milliliter = ml [not Ml]  Do not use p for per. miles per hour = mi/hr [not mph]
Slide 15: Write the correct units mm = millimeter mg = milligrams L = liter Mg = Megagram m = meter dam = decameter g = gram cm = centimeters ns = nanosecond
Slide 16: Which number is bigger? 4 cm or 4 hm 10 km or 10 mm 12g or 12 kg
Slide 17: What will we measure? Length Distance between two points. Mass Amount of material in an object. Temperature Amount of heat a material has. Volume Amount of space an object takes up.
Slide 18: What are BASE UNITS? A base unit is the standard unit of measurement that we will use to measure. We will add prefixes to the base units.
Slide 19: Measuring LENGTH The SI base unit of measurement for length is the METER. 1 meter = 1m Your desk is about one meter tall. You can use a METRIC RULER or a METERSTICK to measure length.
Slide 21: Other units of length If you wanted to measure between cities, you would use KILOMETERS. A kilometer is equal to 1,000 meters. If you wanted to measure small lengths, you would use a centimeter or a millimeter. There are 100 centimeters in a meter. Just like there are 100 cents in a dollar. There are 1000 millimeters in a meter.
Slide 22: SURFACE AREA Surface area is the space that a surface covers. If you wanted to buy carpet or floor tile, you will have to know the SURFACE AREA of the floor.
Slide 23: Calculating SURFACE AREA To find the area of a rectangle, multiply length X width. AREA = Length X Width What is the area of this rectangle? 10cm 5cm A= LXW = 10 cm X 5 cm = 50 cm2
Slide 24: Practice! How much carpet do you need to cover the floor in a room that measures 7 meters long and 5 meters wide? L=7m W=5m A=LXW A= 7mX5m A = 35m2
Slide 26: Measuring VOLUME of a liquid The SI base unit of measurement for volume is the LITER. 1 Liter = 1L You will use different units and tools to measure volume of a liquid or a solid. You can use a GRADUATED CYLINDER to measure the volume of a liquid.
Slide 28: Graduated cylinders measure in mL or milliliters. The plastic ring around a graduated cylinder prevents breaking. To read a graduated cylinder: Move to eye level. Read the bottom of the meniscus.
Slide 29: How much water is in this graduated cylinder? Image from ChemPages Laboratory Resources http://jchemed.chem.wisc.edu/JCESoft/Programs/CPL/Sample/modules/gradcyl...
Slide 30: VOLUME of a solid If you are trying to find the volume of a solid, you cannot pour it into a graduated cylinder. Methods: Water displacement Calculating volume
Slide 31: Water Displacement
Slide 32: What steps will you take to measure with water displacement? Put water in the graduated cylinder. Record the measurement. Tilt the graduated cylinder to the side. Gently lower the object into the graduated cylinder. (Make sure that the whole object is under water.) Record the measurement. Water & Object – Water = Object’s volume REMEMBER 1 ml = 1 cm3 = 1 cc
Slide 33: Calculating Volume of a Block To find the volume of a regular (block or box shaped) solid, you need to measure the length, width and height IN THE SAME UNIT and multiply these three numbers together. V= L X W X H What is the volume of the black cube? What is the volume of the bigger cube? Volume = length X width X height V = 3 cm X 2 cm X 2 cm V = 12 cm3
Slide 34: Units of VOLUME 1 liter = 1 L 1 milliliter = 1 mL 1 centimeter cubed = 1 cubic centimeter = 1 cm3 = 1 cc 1 L = 1000 mL 1 mL = 1 cm3 1 L = ___________cm3
Slide 36: Measuring MASS The SI base unit of measurement for mass is the GRAM. 1 gram = 1g A paperclip is about 1 gram. You can use a TRIPLE BEAM BALANCE or an ELECTRONIC SCALE to measure mass.
Slide 38: Using an electronic balance They are very sensitive. DO NOT place heavy objects or press down with your hand. DO NOT put liquid, powder or crystals directly on the tray.
Slide 39: Other units of mass If you wanted to measure large masses you would use KILOGRAMS. 1 Liter of pop has a mass of about 1 kilogram. If you wanted to measure the mass of smaller objects, you would use milligrams or centigrams. When have you heard someone say milligrams?
Slide 41: Measuring TEMPERATURE The SI base unit of measurement for temperature is Kelvin (K). A more common unit is DEGREES CELSIUS. 1 degrees Celsius = 1ºC You can use a THERMOMETER to measure temperature.
Slide 43: Look at the picture to compare ºF and ºC.
Slide 45: Measuring TIME The SI base unit of measurement for time is the SECOND. 1 second = 1s We will use a STOPWATCH to measure time in science class.
Slide 46: Time (s)
Slide 47: How do you change from one unit to another? From another system to metrics or changing metrics FACTOR LABEL METHOD. From metrics to metrics, MOVE THE DECIMAL.
Slide 48: from Industry Week, 1981 November 30
Slide 49: FACTOR LABEL METHOD Write down what you know. Write down what you know about those two units. Multiply by a fraction. Cancel out like units. Do the math.
Slide 50: Let’s Practice! 600 mm = ? m 1 m = 1000 mm or 1 mm = 0.001 m 600 mm X 1m = 0.6 m 1000 mm
Slide 51: 0.35 liters = ? milliliters
Slide 52: 1050 grams = ? kilograms
Slide 53: 4 years = ? days
Slide 54: 20 kilograms = ? milligrams
Slide 55: 3500 seconds = ? hours
Slide 56: Moving the decimal Metric unit conversion is simply a matter of moving the decimal in the correct direction and the correct number of places.
Slide 57: Write this chart: kilo hecto deca BASE UNIT deci centi milli gram (g) k h da d c m meter ( m) 1000 100 10 0.1 0.01 0.001 liter (L) 103 102 101 10-1 10-2 10-3 second (s) Find the unit you are starting with. Find the unit you want to change to. Count the number of spaces you have to move. Which way did you move? Move the decimal in that direction that number of spaces.
Slide 58: kilo hecto deca BASE UNIT deci centi milli gram (g) k h da d c m meter ( m) 1000 100 10 0.1 0.01 0.001 liter (L) 103 102 101 10-1 10-2 10-3 second (s) Convert these: 35 ml = ? dl 2000 mm = ? km 0.752 hg = ? cg
Slide 59: How can we remember the order of the chart? Kids Have Dropped OVER Dead Converting Metrics Kilo Hecto Deca OVER Deci Centi Milli meter liter gram What is your mnemonic device?
Slide 60: DENSITY Pages 94- 95
Slide 61: ORGANIZING DATA Pages 210-211
Slide 62: ANALYZING DATA Pages 212-213
Slide 63: Images copied from: http://lamar.colostate.edu/~hillger/brownridge.ht http://invsee.asu.edu/Modules/size&scale/unit2/u

source: http://www.slideshare.net/plenning/