1. Chapter 1 Includes SI units, first lab equipment, and unit conversion
SI and Metric Basics
Chapter 1
Includes SI units, first lab equipment, and unit conversion

2. Amount of substance (n)
The 7 SI Units
Quantity
Unit
Length (l)
Meter (m)
Mass (m)
Kilogram (kg)
Time (t)
Second (s)
Temperature (Tx)
Kelvin (K)
Electric current (I)
Ampere (A)
Amount of substance (n)
Mole (mol)
Luminous intensity (?)
Candela (cd)

3. Derived units
Units that are combinations of the base units by multiplication or division.
What to look for:
Units that are fractions (m/s or g/cm3),
Units that are products (N*m)
Units that have powers (cm3),
Units other than the 7 SI units.

4. Multiplied or divided units
Treat units as variables:
(m)(m) = m2
(mol)(mol)(mol) = (mol)3
s2/s = s
m3/m = m2
3m + 6m = 9m
(x)(x) = x2
Which of these examples does not show the making of a “derived unit”?

5. Multiplies base unit by…
4 Common Prefixes
Prefix
Symbol
Meaning
Multiplies base unit by…
Mega M
Million
1,000,000
Kilo k
Thousand
1,000
Centi c
Hundredth
0.01
Milli m
Thousandth
0.001

6. Amount of substance (n)
The 7 SI Units
Quantity
Unit
Length (l)
Meter (m)
Mass (m)
Kilogram (kg)
Time (t)
Second (s)
Temperature (Tx)
Kelvin (K)
Electric current (I)
Ampere (A)
Amount of substance (n)
Mole (mol)
Luminous intensity (?)
Candela (cd)
Take a moment to notice here that the “official SI unit” for mass is not a plain base unit. It is grams with the prefix kilo attached, meaning “1,000 grams”!

7. Wal-Mart Observations
Solids in bottles are usually measured in grams or kilograms (that’s mass).
Liquids in bottles are usually measured in milliliters or liters (that’s volume).

8. Prefix powers of 10 Mega is 106 (1,000,000) Kilo is 103 (1,000)
Centi is 10-2 (0.01)
Milli is 10-3 (0.001)
Do you notice any pattern here?
These can be used in metric conversions.

9. “Powers for Prefixes” Metric Conversion
Replace a unit prefix with its power of ten.
Multiply number of units by power of 10.
Write new number and a unit with no prefix.
Practice until you are a master of substituting powers for prefixes

10. Power for Prefix Example
Given: 17 kg = ? g
Known:
kg means kilogram
Kilo means 103
17 kg = 17 (103) grams
17 (103) grams = 17,000 grams

11. Metric Conversion Stairway
To change a number with a prefix (such as 15 cm) to a number without a prefix (such as m), do the following:
Remember that all you are just switching decimal places.
Think about which units are larger and which ones are smaller.
Use the following chart

12. Metric Conversion Stairwayk
kilo h da b
basic d c
centi m
milli

13. Using the Stairway example
Given: 15 cm
Desired unit: meter
Meter has no prefix, so we consider it basic.
From the centi step, note how many steps it is to the basic step.
It is two steps to the left.
Move the decimal two places to the left to convert 15 cm to 0.15 m.

14. Stairway Observations
Moving from right to left, the answer will be a smaller number than the given.
Moving from Left to Right, the answer will be a larger number than the given.
The two numbers’ units make the values equivalent.
There are seven steps on the stairway. Others could be added.

15. Finding Density
If you know both the mass and the volume of an object, you can find the density of the object.
Here’s how:
Divide the mass by the volume.
Try the example on the next slide.

16. Density Example Given: Formula: D = m / V Numbers in the formula:
Mass of object = 2,000 g
Volume of object = 140 cm3
Formula: D = m / V
Numbers in the formula:
D = 2,000 g / 140 cm3
Answer: 14.3 g/cm3

17. Finding Age
To find your age in metric units, we will have to convert years to seconds. Here’s how:
Turn years to days ( days per yr)
Turn days to hours (24 hr per day)
Turn hours to minutes (60 min per hr),
Turn minutes to seconds (60 sec per min)

18. Age Example Try converting 16 years to seconds.
16 yr ( days / yr) = 5,844 days
5,844 days (24 hr / day) = 140,256 hr
140,256 hr (60 min / hr) = 8,415,360 min
8,415,360 min (60 sec / min) = drumrollllll
504,921,600 sec

19. Factor Labels
In the example we just used, each number was labeled with a unit.
Mathematically, the units are changed in each step
From years to days to hours to minutes to seconds.
One unit is cancelled out in each step until the desired unit is reached.

20. Turning Pounds into Kilograms
If you ever travel internationally, it may be useful to know your weight in SI units. Here’s how to do it:
Remember that there are 2.2 lbs per kilogram.
Take your weight and divide it by 2.2 lbs / 1 kg.
Let’s try an example.

21. Pounds to kilograms example
Given: A man weighs 215 lbs.
Conversion factor: 2.2 lbs / kg
Divide: 215 lbs / (2.2 lbs / kg) =
Answer: 97.7 kg
Notice the unit kg is the only one left. The lbs units have cancelled out.

22. First Lab Equipment
We will be using the following pieces of special lab equipment in our first lab.
Beaker
Graduated cylinder
Temperature probe
TI-84 Graphing Calculator

23. Beaker A cup marked for approximate liquid measurements.
Not very accurate measurements.

24. Graduated Cylinder
Cylinder marked with lines for measuring liquid volumes accurately.
Sometimes used in finding solid volumes dropped into the liquid.

25. Temperature Probe
A stainless steel thermometer used with the TI-84 graphing calculator
An EZ-link is used to connect the probe to the calculator.