THURSDAY, SEPTEMBER 19, 2013 LT: I can conduct safe lab experiments & use appropriate measurement tools correctly. EW: List the base SI units for length, volume and mass. Today: Metric System/Measurement Review Notes Finish Procedure

The Metric System & Measurement

B ASIC U NITS Mass: gram (g) Length: meter (m) Volume: Liter (L) or (l) Temperature Celsius ( ° C) or Kelvin (K)

C ONVERTING Base 10 system Move decimal right – X 10 move decimal left - ÷ 10 Converting bigger to smaller unit move decimal to the right; the equivalence is bigger. ex. meters to centimeters Converting smaller to bigger unit move decimal to the left; the equivalence is smaller. ex. meters to kilometers Let’s see how this works!

T HE C ONVERSION L ADDER Basic Unit To convert to a smaller unit (going down the ladder) move the decimal to the right, or multiply To convert to a bigger unit (going up the ladder) move the decimal to the left, or divide Kilo units Hecto- 100 units Deka- 10 units deci- 0.1 units centi units milli units

LET’S PRACTICE Use the ladder method to find these equivalences: 1) 2 g = __________mg Remember, count the number of steps you need to take on the ladder. If you are going up the ladder, move the decimal that many places to the left. If you are going down the ladder, move the decimal that many places to the right.

LET’S TRY A FEW MORE… 2) 1000 ml = ____________ Kl 3) 500 m = _____________cm Now for a few challenging ones 4) cg = __________Dg 5) HL = _________dL

CONVERTING BETWEEN SYSTEMS Must know conversion factor (ratio showing how many units of one system are in 1 unit in the other system). Handy conversion factors: 2.54 cm/1 in km/1 mi cm/1 ft in/1 m

EXAMPLE & PRACTICE! EX. If 2.2 lbs equals 1 kg, how many kgs is 525 lbs? Set up dimensional analysis: 1. Write given measurement & X 2. Set up conversion factor – put unit you are converting from in the denominator. 3. Put unit you are converting to in numerator. 4. Put 1 next to larger unit and how many equals one next to smaller unit.

525 lbs X 1 kg 2.2 lbs 5. Cancel units 6. Do the math! Try this! Bode’s beautiful tail is 2.7 ft. long. How many centimeters is Bode’s tail? Remember there are cm in 1 ft.

SIGNIFICANT DIGITS Meaningful digits in a measured quantity. Last digit may be uncertain (an estimate), but it is still significant. When doing calculations with measurements with different amounts of significant digits, your answer can only have as many digits as the least number you are working with. If your answer has more, you must round your answer.

EXAMPLES How many significant digits in 5.24? If I divide 5.24 by 3.8, how many significant digits can I have in my answer? My calculator gave me the answer What number should I report?

USING MEASUREMENT EQUIPMENT Distance – ruler or meter stick Volume – graduated cylinder

Mass – triple beam balance digital balance Temperature – thermometer digital probe Tutorial

TUESDAY, SEPTEMBER 17, 2013 LT: I can conduct safe lab experiments and use appropriate measurement tools correctly. EW: Kg = ? cg? in. = ? cm? (2.54 cm = 1 in.) Today: Measurement Lab

WEDNESDAY, SEPTEMBER 18, 2013 LT: I can conduct safe lab experiments and use appropriate measurement tools correctly. EW: If the triple beam balance can mass to the 10 th of a gram, how many decimal places should be in your mass calculation? Today: Homework Quiz Measurement Lab – You will be assessed today on participation, thoroughness and neatness of your lab work - +4 points possible

CH. 1 HOMEWORK QUIZ 1. The English System of measurement is one system of measurement. What is the other system of measurement? 2. What is the prefix that indicates 1000 items or base units (it means 1000)? 3. What is an independent variable? 4. What is the responding (dependent) variable? 5. Convert 650 millimeters (mm) to meters (m) 6. Draw a picture of an xy graph. (label the x AND y axis)

MEASUREMENT LAB First lab in Composition Lab Note Book! First page – Table of Contents Third page – Title: Measurement Lab Directions: You will visit 6 stations. Provide a clear title in your book for the work you do at each station! Follow the directions posted at each station, doing the written work in your Comp Book. Station 7, if time allows. Finish by answering Focus Questions

MEASURING FOCUS QUESTIONS When measuring, for which digit do scientists expect uncertainty? Explain why it is still significant and should be reported. Why would you zero a balance before each use? Why would you zero the weighing dish before placing the substance in it? When you used 2 different technologies to measure mass or temperature, did the measurements match exactly? Why might they have been different? List and explain 3 safety rules you followed in this lab.