Shorten the following statement: Dear Ayla, Today, while walking home from school, I got drenched in the rain. I can't believe it! My book bag wasn't zipped all the way, and my papers got soaked. I can't read our homework assignment. Can you send it to me? Thank you so much! Jenny

Read the following statements out loud to your table partner The population of the world is about 7,117,000,000. The distance from Earth to the Sun is about 92,960,000 miles. The human body contains approximately 60,000,000,000,000 to 90,000,000,000,000 cells. The mass of a particle of dust is kg. The length of the shortest wavelength of visible light (violet) is meters.

Scientific Notation

In science, we deal with some very LARGE numbers: 1 mole = In science, we deal with some very SMALL numbers: Mass of an electron = kg Scientific Notation

Calculate the mass of 1 mole of electrons: kg x x ???????????????????????????????????

Scientific Notation: A method of representing very large or very small numbers in the form: N x 10 n N x 10 n  N is a number between 1 and 10  n is an integer

Step #1: Insert an understood decimal point. Step #2: Decide where the decimal must end up so that one number is to its left up so that one number is to its left Step #3: Count how many places you bounce the decimal point the decimal point Step #4: Re-write in the form N x 10 n

2.5 x 10 9 The exponent is the number of places we moved the decimal.

Step #2: Decide where the decimal must end up so that one number is to its left up so that one number is to its left Step #3: Count how many places you bounce the decimal point the decimal point Step #4: Re-write in the form N x 10 n 12345

5.79 x The exponent is negative because the number we started with was less than 1.

PERFORMING CALCULATIONS IN SCIENTIFIC NOTATION ADDITION AND SUBTRACTION

Review: Scientific notation expresses a number in the form: N x 10 n 1  N  10 n is an integer

4 x x 10 6 IF the exponents are the same, we simply add or subtract the numbers in front and bring the exponent down unchanged. 7 x 10 6 ADDITION

4 x x 10 6 The same holds true for subtraction in scientific notation. 1 x 10 6 SUBTRACTION

4 x x 10 5 If the exponents are NOT the same, we must move a decimal to make them the same.

4.00 x x x x 10 6 Move the decimal on the smaller number! 4.00 x 10 6

A Problem for you… 2.37 x x 10 -4

2.37 x x Solution… x 10 -6

x Solution… x x 10 -4

Another problem for you… 2.37 x x 10 -4

2.37 x x Solution… x 10 -6

x Solution… x x 10 -4

PERFORMING CALCULATIONS IN SCIENTIFIC NOTATION MULTIPLICATION & DIVISION

(4 x 10 6 ) X (2 x 10 3 ) Only the numbers are multiplied; the exponents are added =8 x 10 9 MULTIPLICATION

A Problem for you… (2.0 x ) X (3.0 x ) Only the numbers are multiplied; the exponents are added =6.0 x

(4 x 10 6 ) X (2 x 10 3 ) Only the numbers are multiplied; the exponents are added =8 x 10 9 Another problem for you…

(8 x 10 6 ) ÷ (2 x 10 1 ) Only the numbers are divided; the exponents are subtracted =4 x 10 5 DIVISION

A Problem for you… (12 x ) ÷ (2 x ) Only the numbers are divided; the exponents are subtracted =6 x 10 -4

Measurement – a review  Volume  Mass

Reading the Meniscus Always read volume from the bottom of the meniscus. The meniscus is the curved surface of a liquid in a narrow cylindrical container.

Read Mass _ _ _. _ _ _ 114 ? ? ?

Read Mass More Closely _ _ _. _ _ _