Work out the following in your notebook while I check notes Page 53 #4 Page 62 #14

Learning Targets Be able to use scientific notation and significant figures properly.

1) Discuss Scientific Notation 2) Notes on Significant Figures 3) Begin Homework

Move the decimal point so that there is 1 digit to the left of the it and use powers of 10. Numbers greater than 1 have positive exponents: 1269 = x = 1 x 10 2 Numbers smaller than 1 have negative exponents: = 3.5 x = 7.46 x 10 -2

Your calculator doesn’t understand the notation x10 exp Graphing Calculators use EE function (2 nd comma) Example: 2 x = 2 E -2

Measurements must indicate accuracy What is the width of this apple & shadow?

10cm, 20cm, 30cm, 0cm, 10cm, 20cm, 30cm, 0cm, Apple + Shadow Width = 14 cm Apple + Shadow Width = 14.4 cm

1. All non-zero digits are significant 13 cm = 2 sig figs 13.2 cm = 3 sig figs 2. If there is a decimal point, scan number from left to right and begin counting all numbers with the first non-zero digit cm = 4 sig figs 10. cm = ( → ) sig figs

“Right to the Point”

3. If there is NOT a decimal point, scan number from right to left and begin counting all numbers with the first non-zero digit 1400 = 2 sig figs 10 = 1 sig fig ( ← ) 21Skip

10 cm represents a rounded measurement 10. cm represents a more exact measurement 20cm, 0cm, 10cm, 20cm, 30cm, 0cm,

4. All exact numbers have an infinite number of sig figs 4 apples It is not possible that I have 3.9 apples rather than 4 apples. Only measured values require sig figs.

5. All numbers written before “x 10 exp ” in scientific notation are significant 6.02 x atoms = 3 sig figs 1.0 x 10 4 mL = 2 sig figs How can you write 1000 cm with two sig figs? (1000 = 1 sig fig or = 4 sig figs) 1.0 x 10 3 cm

Accuracy must be retained during calculations divide 17.37cm by 4.79cm (calculator answer ) NO WAY…from two decimal places and 3 or 4 sig figs of accuracy to 10 sig figs! Accuracy can’t be created via calculation

Round your answer to the least number of decimal places in any of the factors 12.3cm cm = cm 13.71cm – 2cm = cm Only 1 decimal place No decimal places 12

Round your answer to the least number of sig figs in any of the factors 1.3 cm x 15.4 cm = cm cm 2 ÷ 2.82 cm = cm Only 2 sig figs Only 3 sig figs

Homework 1) Read & take notes over 3.3, 3.4, & 3.5 (pg 63-76) 2) Page 7 and 8 of Math and Measurement Packet Suggested Problems p. 53 #1-3; p. 62 #13,14,16; p #39,48,67