Back to the Basics

Science Lab Equipment

Graduated Cylinder

• Measure about 26.1 mL

Scale

• Weigh the object

Ruler

• Measure the length of the object

SI Units

• International System of Units (SI)

Metric Prefixes

BIGGER

SMALLER

kkilo

hhecto

dkdeca

BASE

(m, g, L)

ddeci

ccenti

mmilli

BIG

SMALL

10

1000

100

1

.1

.01

.001

1. Determine whether you are going up the ladder or down the ladder.•If you go up, move the decimal to the left.•If you go down, move the decimal to the right.

2. Use the ladder to determine how many places to move the decimal.•The number of steps on the ladder is equal to the number of decimal places.

• Write the correct units with your answer.

How do you convert between metric units?

• Practice Problems1. 0.7834 mg = ____________ g

2. 100 cm = ______________ m

3. 345,000 kg = ____________ g

4. 2.5 mm = _______________ hm

5. 3.46 cg = ________________ mg

6. 1.00 km = _______________ cm

Dimensional AnalysisConvert 892cm to meters……①Find the conversion factor

1) What unit is bigger? (This will have the value of 1)

2) What unit is smaller (This will have the big number)

3) What is the difference between them (Count how many you pass on the chart, each

one is 101 more)

②Make the units cancel to get the units you want

Conversions①3.46 cg = _____ mg

②1.00 km = _____ cm

③1470 mg = ______ μg

④15.5 ng = _____ dg

⑤100 cm = ______ pm

Conversions①8.9g/cm = _______ kg/m

②4.23m/L = _______ cm/mL

③19.6cm/L = ______ m/mL

④2.5g/m = ______ g/cm

Scientific Notation• Method of writing very small or very large numbers

– A positive exponent means the decimal moved to the left. A negative exponent means the decimal moved to the right

Scientific Notation• 602,200,000,000,000,000,000,000 = ?

– Step 1: Make the Coefficient less than 10 and more than 1.

– Step 2: Find out how many places over the decimal has to move to give you the number in step 1.

Scientific Notation①5,300,000 = ?

②4,302,000,000 = ?

③-24,500 = ?

④.000034 = ?

⑤-.0000007 = ?

Scientific Notation①5.3 x 104 = ?

②7.02 x 108 = ?

③-3.21 x 103 = ?

④7.093 x 10-4 = ?

⑤-5 x 10-3

Derive a relationship between the following

17 = 2300 = 1345 = 31000 = 11001 = 4100.0 = 4

Accuracy vs. Precision• Accuracy: How close to the real value

• Precision: How close a series of measurements are to each other

Significant Figures– Rounding Numbers:

-Round up if the digit to the right is between 5-9

59.48 59.5-Drop the number to the right if it’s between 0-

43.84 3.8

Significant Figures Tell You What Number To Round To!

Significant Figures• All Non-zero numbers (1,2,3,4,5,6,7,8,9) are significant• Zeros –

1) Front of number are NEVER significant 0.0071, 0.42, .000099 all have 2 sig. figs

2) Middle of number are ALWAYS significant7003, 40.79, 1.503 all have 4 sig. figs

3) End are SOMETIMES significantAt end AFTER decimal, ALWAYS significant

36.00, 1.010, 9.000 all have 4 sig figsAt end BEFORE decimal, NEVER significant

300, 7000, 20000 all have 1 sig fig

Significant Figures①5.30 = ?

②76009.0 = ?

③1900 = ?

④.0000000891 = ?

Significant Figures• Addition and Subtraction

– Match the number with the least number of decimals• Ex: 13.21 + 4.1 = 17.3

13.21 + 4.100 = 17.3113.21 + 4 = 17

• Multiplication and Division– Match value with fewest number of sig figs

• Ex: 2.00 x 11 =222.00 x 11.0 = 22.02 x 11 = 20