 # Instructional Objective: 1.Identify Standards of Measurements 2.Learn about SI units.

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Instructional Objective: 1.Identify Standards of Measurements 2.Learn about SI units

Standards of Measurements Standard: Is an exact quantity that people agree to use for comparison

International System of Units (SI Units) *came from the French words “Le Systeme Internationale d’Unites”. Are universally accepted and understood by Scientists Each type of SI measurements has a base unit

SI comes from the French La Systeme Internationale. SI and metrics use the same units and processes. There are certain steps to follow when converting between units of metric measure: 1--Use the following short cut chart k h da * d c m 2--Find your original place on the chart by looking at the problem to identify the number with the unit (mark that place) 3--Find your target place on the chart by looking at the problem to identify the number without the unit (mark that place differently) 4--Count how many places you would need to move between the original and target places 5--Always move your decimal in the direction you moved on the chart from the original to the target 6--Rewrite the number given in the problem and apply steps 4 and 5 to the number 7--Write the answer in the blank provided

SI Base Units

Common SI Prefixes

Now let’s see how well you can perform some conversions!! Example problems 10 km = _____ dm 0.1 hm = _____ m 1cm = _____ hm 0.01 m = _____ mm 100 dg = _____ dag 10 hg = _____ kg 0.1 mg = _____ dg 0.001 cg = _____ mg 1 kg = _____ g 0.01 dag = _____ cg

The centigrade (Celsius) scale temperature (K) = temperature (°C) + 273.15 the melting point of water is = 0°C = 273.15 K the boiling point of water is = 100°C = 373.15 K

The boiling point *is the temperature at which the vapor pressure of a liquid is one atmosphere. *Units - K (Kelvin)

The Fahrenheit scale the melting point of water = 32°F the boiling point = 212°F.

The SI unit of temperature is Kelvin (K). Notice that there is no degree sign used with the abbreviation. To covert from Celsius to Kelvin temperatures: C--> K+ 273 K--> C- 273 CelsiusKelvinFahrenheit Freezing: 0 273 32 Boiling: 100 373 212

Dervied units: are combinations of SI units. Volume: amount of space occupied by an object. Volume=Length X Width X Height V= l X w X h This is used to calculate the volume of a cube and combines three length measurements together. Density: the mass per unit volume of a material. Density=Mass/Volume D=m/V This is a combination of units of mass and volume.

Density of the regular object  Mass- find the mass of the object  using a balance  Volume- To find the volume by measuring the length, width, and height.  Then calculate density=mass/volume

Density of the irregular object  Mass- find the mass of the unknown  using a balance  Volume- To find the volume, first measure the water that can immerse the irregular object in a graduated Cylinder.  Then dropped the object in the cylinder and note the displacement measurement.  Density = mass/volume.

Length- the basic unit of length is the meter. Meter- SI unit of length - the distance between the doorknob and the floor. Scientific Measurement

 Volume- is the amount of space that something occupies.  Liter - SI unit for volume....- A little more than a quart... - Solid objects can have volumes in cubic centimeters Scientific Measurement

Mass- is the amount of matter an object contains. Kilogram- the basic SI unit for mass.  About 2.25 pounds.  A smaller unit is the gram. Scientific Measurement

Easier to use because it is a decimal system Every conversion is by some power of 10. Much easier to use when doing calculations. The Metric System

A metric unit has two parts A prefix and a base unit. prefix tells you how many times to divide or multiply by 10. The Metric System

Length - meter - m Mass - gram - g Time - second - s Temperature- Kelvin (K) or ºCelsius (ºC) Volume - Liter - L SI Base Units

kilo k 1000 times hecto h 100 times deca D 10 times kilometer - equals 1000 meters or about 0.6 miles SI Prefixes

deci d 1/10 centi c 1/100 milli m 1/1000 centimeter - 1/100 of a meter or less than half an inch SI Prefixes

 Line up from zero not the end of the ruler  Small numbered divisions are centimeters (parts are mm) Measuring Length 01234

Measuring Volume  Use a graduated cylinder.  Hold it level with your eye.  Read the bottom of the curve.  Measures in milliliters mL.  A meniscus is the curvature of the surface of the water 10 20 30

Weight is a measure of the pull of gravity and, mass is the amount of matter. The weight of an object can change, but an object’s mass is constant. Mass vs Weight

 Use a triple beam balance  First zero the balance.  Then place object on pan.  Then move largest weight first, until pointer tips to right and move back one notch. Triple Beam Balance Use

Move next smallest weight, until pointer tips to right and move back one notch. Move smallest weight, until pointer is at mid-position. When balanced, add up the weights. Triple Beam Balance Use

012345678910 0 20304050607080901000 200300400500 Triple Beam Balance

Press on button to turn on. If balance is not on zero, press zero button. Place object on pan and, record mass in grams. Turn balance off at end of lab period. Electronic Balance Use

how far you have to move on this chart, tells you how far, and which direction to move the decimal place. Metric Conversions khDdcm m L g

l Change 5.6 mg to kilograms. l starts at milli position and move six places to the left. Metric Conversions khDdcm m L g

 move the decimal point six places to the left 0.0000056  5.6 mg = 0.0000056 kg Metric Conversions khDdcm m L g

 Change 5.6 m to millimeters  starts at the base unit position and move three places to the right. Metric Conversions khDdcm m L g

 move the decimal point three to the right 5600.  5.5 m = 5600. mm Metric Conversions khDdcm m L g

convert 25 mg to grams convert 0.45 km to mm convert 35 mL to liters Metric Conversions khDdcm m L g

 Density- tells you how much matter is packed into a given volume.  Calculated by dividing mass by volume ( D = M ). V Scientific Measurement

Calculate the density of an object with a mass of 25 g & a volume of 5.0 mL..D = M = 25 g = 5.0 g/mL. V 5.0mL Density Problem

Instructional Objective: 1.Learn the metric system 2.Learn the scientific notions Review Questions: 1. 4578hg to mg____________________ 2. 4.29cm to dkm ______________________