How big is BIG? Or How small is SMALL? Do Now (Begin NEW week 2): OBJECTIVE: 1. Describe quantities using factors of 10. TASK: 1. Pass forward week 1 Do Nows 1. Make a “metric bingo” card. Draw a 3x3 square, and randomly place the prefixes G, M, k, d, c, m, and µ in the boxes (note: 2 squares will have duplicate symbols). See board for example.

Let’s Get This Straight. The SI (aka metric) system of measurement is used in science. The unit of length is the meter, m. 1 m = about 3 feet To the nearest “factor of 10,” you are about 100 m tall. (remember: 100 = 1) If you were 1,000 times SMALLER…(10-3)

Homo sapiens: 1-3 m height If you were 1,000 x smaller, you would be 1-2 mm in size… (10-3) about as big as this flea

1,000 times smaller than that? No Way! Yes, way! In the last example, you were about 1 millimeter tall. Scientists write that number as 0.001 m, or 10-3 m. Factors of 10 are how science keeps track of how big or small things are. Biologists study living things (and parts of living things) from 10-9 (nm) to 103 (km) in size.

If you were 103 m tall… KILO A blue whale would easily fit in your hand. The largest living organism (The Humongous Fungus) covers an area with a width of over 3 km!

The Humongous Fungus: Armillaria ostoyae Found in trees and soil across an area of nearly 2,400 acres. Mass estimate range: 7,500 tons to >35,000 tons (~ 107 kg) Age estimate: 1,900 – 8,650 years

On the other hand, at 10-3 m, milli A human hair would look like this! You’d be as big as a single grain of sugar

1,000 times smaller than 1,000 times smaller! You’d be 10-6 m (1 µm) tall, about as big as a small bacterial cell

Catch a Cold! The softball sized object is a model of the virus that causes the common cold. If you were 10-6 m tall it would be life-sized

When Good Protists Go Bad… If you were 10-6 m tall, cells like these could SWALLOW YOU WHOLE!

Look closely! The bumps on the virus are proteins that make up the outer layer of the virus. What is protein?

Proteins are BIG??? YES! Proteins are huge molecules made up of thousands and thousands of atoms.

In biochemistry, 10-6 m is REALLY BIG! CELLULOSE (sponge) DNA

ATOMS ARE more than 1000x smaller than that! Chemistry is nano-scale

A quick review… 103 m tall: A blue whale fits in your hand. (kilometers) 100 m tall: your natural size. (meters) 10-3 m tall: human hair is as thick as a poster tube. You are the size of a single grain of sugar. (millimeters) 10-6 m tall: viruses are softball-sized, and you can get eaten by a paramecium! (micrometers) 10-9 m tall: you can play catch with atoms! (nanometers)

Powers of 10, 1977 http://www.teachertube.com/viewVideo.php?video_id=119236 Animation: http://htwins.net/scale2/

Scientific Notation How scientists and engineers do math with really big and really small numbers Example: 93,000,000 mi = 9.3 x 107 mi Metric prefixes help too! (more on that later) Example: 0.002 m = 2 mm

Basic Facts About Scientific notation Positive exponents represent large numbers. To convert a number into scientific notation Move the decimal place to the left until there is only one digit left. 2,400  2.400 = 2.4 Count the number of places moved. This is the exponent 2,400 = 2.4 x 103

Basic Facts About Scientific notation NEGATIVE EXPONENTS REPRESENT SMALL NUMBERS To convert a number into scientific notation Move the decimal place to the right until there is only one digit (not zero) to the left. 0.000,065  6.5 Count the number of places moved. This is the exponent, remembering SMALL NUMBERS HAVE NEGATIVE EXPONENTS 0.000,065 = 6.5 x 10-5

To convert to standard Notation Do the process in reverse. 6.3 x 105 630,000

Assignments Become an expert at using factors of 10 to represent big and small numbers. Complete the Factors of 10 worksheet.