OPEN UP YOUR HOMEWORK AND COMPARE IT TO THE ANSWER KEY IN SCHOOLOGY We will go into break out rooms to get help from peers in a moment Break out Rooms While in the breakout rooms, use your peers to get help on the questions you missed. Each group can choose one question for me to review before we move on to the lesson. Group 1 Group 2 Group 3 Group 4 Group 5 Group 6 SCIENTIFIC NOTATION Machart Physics Why do we use Scientific Notation Mass of the Earth is : 5,972,000,000,000,000, 000,000,000 kg Mass of a Proton is: 0.00000000000000000 00000000016726219 kg It is called Scientific Notation because: ■ Our numbers are based on units of 10. ■ Our Standard Units are based on units of 10 Example: 5.4 x 10^7 What are we really saying? 8 x 10^5 8 x 10 ^-5 ■ 8 x 10 x 10 x 10 x 10 x 10 ■ 8 ______________________________ 10 x 10 x 10 x 10 x 10 But we can also look at it as a decimal point mover. 3.25 x 10 ^ 2 68.5 x 10 ^-2 When the exponent is Positive the number is getting bigger. When it is negative the number is getting smaller. Zeros can always be place holders. 5.2 x 10 ^ -3 3.25 x 10 ^3 Convert 61,425 to Scientific Notation REVERSE! Step 1. Note where the decimal is now. 61,425 Step 2 Note where you want the decimal to be (You want a number between 1 and 9 Step 3 If you have made the number smaller, it will be the exponents job to make it bigger so you need a positive number. If you have made the number bigger then the exponents job is to make it smaller so you need a negative exponent. 0.2134 What if I’m adding or subtracting two numbers in Scientific Notation? ■ 1. Use a calculator. (It’s funny…. But I’m serious) Then the exponents don’t matter. ■ 2. If you must do it by hand: Your exponents must match. – 3.2 x 10^3 + 4.7 x 10^3 = YES This is okay. You just add the base numbers and then put the same x10^3 on them. – 4.5 x 10^2 + 3.5 x 10 ^3 = NO This is NOT okay. You must convert one of them to match the other – Here’s how you do that…. You can always just write out the number and convert it back. OR If you are making the exponent smaller then the decimal moves to the right. If you are making the exponent bigger then the decimal moves to the left ■ 4.5 x 10^2 + 3.5 x 10 ^3 But Multiplication and Division are way easier. ■ 3 x 10^4 * 2 x 10^6 Multiplication: Just multiply the base number then add the exponents together. Division: Just divide the base number then subtract the exponents from each other. 9 x 10 ^4 divided by3 x 10^2 LET’S PRACTICE EXIT TICKET