Significant Figures/Dimensional Analysis

Objective: Today I will be able to: Apply significant figures to solving problems Apply dimensional analysis to solving problems Informal Assessment – monitoring student questions and interactions as they complete the practice problems Formal assessment – analyzing student responses to the exit ticket and practice problems Common Core Connection Make sense of problems and persevere in solving

Lesson Sequence Evaluate: Warm-Up Engage/Elaborate: Real life Dimensional Analysis Problems Evaluate: Exit Ticket

Warm-Up Solve and record your answer to the correct number of significant figures: 1) 4.276 x 520 = .0025 x 3.15 = 1,538.914 – 390.2 =

Objective Today I will be able to: Apply significant figures to solving problems Apply dimensional analysis to solving problems

Homework Complete the dimensional analysis practice Study for scientific notation quiz on Thursday, September 11

Agenda Warm-Up Dimensional Analysis Notes Real Life Dimensional Analysis Practice Problems Exit Ticket

Dimensional Analysis Notes

Conversion Factor 12 inches 1 foot 7 days 1 week ½ A Fraction that is equal to the number one Two quantities that equal the same thing 12 inches 1 foot 7 days 1 week .5 ½

Dimensional Analysis 1 dozen 12 eggs 12 eggs 1 dozen Yes! Q: Do these two fractions equal the same quantity? 1 dozen 12 eggs 12 eggs 1 dozen Yes!

Dimensional Analysis Problem Solving Tips Read the problem Write down what you are given, put it over 1 Write down what you are looking for List all possible conversion factors for the problem Make a road map Solve the problem

Practice Problem 1 Q: How many minutes are there in 10 hours? 10 hours 1. Read the problem 2. Write down what you are given, put it over 1 3. Write down what you are looking for. The number of minutes x minutes 10 hours 1

Practice Problem 1 Cont 1 hour 60 minutes 4. List all possible conversion factors for the problem -We know that one hour = 60 minutes 5. Make a road map Hours ? Minutes 1 hour 60 minutes 60 minutes 1 hour

Practice Problem 1 Cont. 6. Solve the problem We also know that when you multiply, if 2 quantities are placed in opposite corners of each other, they will cancel out For example, Incorrect, the units do not cancel out 10 hours . 1 hour = 10 hours 2 1 60 minutes 60 minutes

Practice Problem 1 cont. 10 hours . 60 minutes = 600 minutes 1 1 hour 7. Solve for Correct Answer! 10 hours . 60 minutes = 600 minutes 1 1 hour

Practice Problem 2 Q: How many minutes are there in 12 weeks? Weeks  Days  Hours  ? Minutes 12 weeks . days . hours . minutes = 1 week day hour 12 weeks . 7 days . 24 hours . 60 minutes = 1 1 week 1 day 1 hour

= 1,048,320 minutes or 1,051,200 minutes (365 days) Practice Problem 3 Q: How many minutes are there in 2 years? Years  Weeks  Days  Hours  Minutes 2 years . weeks . days . hours . minutes = 1 year week day hour 2 years . 52 weeks . 7 days . 24 hours . 60 minutes = 1 1 year 1 week 1 day 1 hour = 1,048,320 minutes or 1,051,200 minutes (365 days)

Practice Problem 4 500 mL . 1 Liter = 0.500 L 1 1000 mL Q: How many liters are in 500 mL? mL  ? L 500 mL . 1 Liter = 0.500 L 1 1000 mL

Practice Problem 5 20 kg . 1000 g . 1000 mg = 2 x 107 mg 1 1 kg 1 g Q: How many milligrams are there in 20 kg? kg  g  ? mg 20 kg . 1000 g . 1000 mg = 2 x 107 mg 1 1 kg 1 g

Dimensional Analysis Practice Complete the practice at your desk. Show all work. Write answer to correct number of sig figs.Will be collected

Exit Ticket Why don’t you count significant figures in a conversion factor? What do you base significant figures on in a dimensional analysis problem. Solve the problem below. Show all work and round to the correct number of significant figures. How many seconds are in the 7 hour school day?