Catalyst

What piece of lab equipment would you use to measure…

The volume of water? The volume of a square block? The mass of a diamond? The temperature of a solution being

heated? The length of the classroom? The density of a weird shaped rock? (CHALLENGE!)

Today’s Agenda

Catalyst Short Diagnostic Standard International Units Prefixes – it just makes too much

sense Accuracy and Precision How accurate/precise are you? Exit Question

Today’s Objectives

SWBAT identify and use SI units and SI prefixes.

SWBAT distinguish between accuracy and precision.

Short Diagnostic

You have 4 minutes to show me what you know!

We will go over the answers while taking notes!

Measurement Notes

Key Point #1: Scientists have a standard international way of measuring volume, mass, and length known as SI

Why do you think scientists do this?

Standard International Units

Volume is the amount of space an object takes up; measured in liters (L) or centimeters cubed (cm3)

Mass is the amount of matter in an object; measured in grams (g)

Length is the distance from one point to another; measured in meters (m)

What unit should you use to answer the following questions???1. How far is it from the Earth

to the Sun?2. How much water can I fit

into the beaker?3. How much matter can we

put on the table before it breaks?

METERS

LITERS

GRAMS

Prefixes

Key Point #2: You can use prefixes to adjust the value of each of these units.

Why would scientists do this?

Well… fine… what are these prefixes?

yotta- (Y-) 1024 1 septillion

zetta- (Z-) 1021 1 sextillion

exa- (E-) 1018 1 quintillion

peta- (P-) 1015 1 quadrillion

tera- (T-) 1012 1 trillion

giga- (G-) 109 1 billion

mega- (M-) 106 1 million

kilo- (k-) 103 1 thousand

hecto- (h-) 102 1 hundred

deka- (da-) 10 1 ten

deci- (d-) 10-1 1 tenth

centi- (c-) 10-2 1 hundredth

milli- (m-) 10-3 1 thousandth

micro- (µ-) 10-6 1 millionth

nano- (n-) 10-9 1 billionth

pico- (p-) 10-12 1 trillionth

femto- (f-) 10-15 1 quadrillionth

atto- (a-) 10-18 1 quintillionth

zepto- (z-) 10-21 1 sextillionth

yocto- (y-) 10-24 1 septillionth

Well… ok, we generally only use a few of the prefixes…

PrefixPrefix MultiplierMultiplier Power of Power of tenten

giga, G1,000,000,000 (billion) grams in a

Gg 109

mega, M 1,000,000 (million) 106

kilo, k 1,000 (thousand) 103

hecto, h 100 (hundred) 102

deka, da 10 (ten) 101

BASE 1 100

deci, d 1/10 (tenth) 10-1

centi, c1/100 (hundredth) of a gram in a

cg 10-2

milli, m 1/1,000 (thousandth) 10-3

micro, µ 1/1,000,000 (millionth) 10-6

nano, n 1/1,000,000,000 (billionth) 10-9

Figure it out! Fill in the blanks!1. 1,000 milligrams = 1 gram2. 10 meters = 1 dekameter3. 1,000,000,000 liters = 1 gigaliter4. _____________ centimeters = 1 meter5. 1,000,000 micrograms = _________

gram6. 200 meters = ____________

hectometers

Figure it out! Fill in the blanks!1. 1,000 milligrams = 1 gram2. 10 meters = 1 dekameter3. 1,000,000,000 liters = 1 gigaliter4. _____________ centimeters = 1 meter5. 1,000,000 micrograms = _________

gram6. 200 meters = ____________

hectometers

1001

2

Having trouble?

1010##

If the number is negative, If the number is positive,

move the decimal to the left move the decimal to the right

Prefixes can be used for all units Let’s use a milli- for an example You can have a…

Milligram – one-thousandth of a gram

Millimeter – one-thousandth of a meter

Milliliter – one-thousandth of a liter

If Lil’ Wayne was really that rich, he’d be singing a mega, a mega, a mega…

Knowing what you know now… Correct your pre-test!

1. A2. D3. D4. B5. D6. A

Who’s a balla?!?!?!?Who’s a shot calla?!?!?

I hope you all are!If you’re not, come to

tutoring!!!!

Precision/Accuracy Activity (15 min)You will need a package of markers, a bulls eye, and a ruler.

Follow the written procedure.Don’t worry about answering questions at the end….yet!

Now that we got measurement down, let’s talk about accuracy

Accuracy

Key Point #3: Accuracy is how close you are to the correct or accepted value of a measurement. Example of GOOD ACCURACY: Throwing a dart close to the bulls eye

Example of GOOD ACCURACY: If something is known to have a mass of 500 g and you measure 499 g

Precision

Key Point #4: Precision is how close a series of measurements are to one another.

REPEATABILITY! Example of GOOD PRECISION:

Throwing a dart and hitting the same spot 3 times in a row

Example of GOOD PRECISION:If something is known to have a mass of 500 g and four students measure it to be 497 g

Good Accuracy

Good Precision

Good Accuracy

Poor Precision

Poor Accuracy

Good Precision

Poor Accuracy

Poor Precision

Group Activity

Please answer questions at the end on the back of your group paper

Please leave group assignment in folder!

Exit Question

Describe the accuracy (A) and precision (P) of 1 & 2.

What prefix/unit would you

use to measure the

volume of cold drink in

a can?

What prefix/unit

would you use to measure

the length of your pinky?