Precision and Accuracy in Science Outline Name: ______

Precision and Accuracy in Science Outline Name: ______Date: ______Period: ____ SC = there is a screencast available at mrsolson.com I. Math Review A. What are the base units of the metric system?

B. What do the following prefixes mean? centi= ______(10-2) mili = ______(10-3) micro =______(10-6) nano = ______(10-9) C. Use a ruler to measure the following:

D. Look at the number below: circle the thousandths place, place a square around the hundredths place. 821.062 E. 1000µl = ______grams. (µl = microliters)

II. Using Math to Analyze Data (SC) A. What is the mean of the following numbers? What is another term for mean? Show your calculation. (4, 6, 4.5, 7)

B. Why is it important to be able to calculate error when conducting an experiment?

C. What is the equation for percent error?

D. While doing a lab, a student found the density of a piece of pure aluminum to be 2.85 g/cm3. The accepted value for the density of aluminum is 2.7o g/cm3. What is the student’s percent error? Show your work. E. A group of students worked on separate teams to measure the length of an object. Here is

their data. a. What is the mean? Show your work.

b. The actual measurement of the object was 2.78 cm. What is the percent error? Show your work.

F. What is standard deviation?

G. Why is it important to know the standard deviation?

H. You will need to have a working knowledge of Microsoft Excel to be successful in this class. Use the screencast to show you the proper way to set up an Excel spreadsheet. We will be using this for our next lab. Fill in the boxes just like you would on the Excel spreadsheet. III. Instrument Calibration (SC) A. Compare and contrast accuracy and precision.

B. Fill in the table.

C. The micropipettes that we will use in this class come in three different sizes each of which measures a different range of volumes. The three sizes are P20, P200 and P1000. These sizes are noted on the top of the plunger button. Fill in the HIGHEST volume that each micropipette can dispense. Size Micropipette Range of Volumes Measured P20 .5 µl -____ µl P200 20 µl -____ µl P1000 100 µl -____ µl

D. What are the following volumes?

E. If the digital readout on the pipette was * then what volume would that be on the following micropipettes?

0 7 0 F. Which micropipette would be appropriate to measure 250 µl? G. Fill in the numbers as they would appear on the micropipette. (from the previous problem)