1. Making Measurements & Using the METRIC SYSTEM
Adv. Honors Chemistry
Braintree High School

2. Types of OBSERVATIONS Quantitative: Qualitative: Tells us how many.
Describes “Quantity”
Describes observations with numbers.
Qualitative:
Tells us about it.
Describes “Quality”
Describes observations with words.

3. Qualitative Vs. Quantitative
His shirt is red.
There are 2 apples left.
The table is 5 meters long.
A blue crystal formed on the bottom of our 100mL beaker.
Her shirt is 100% cotton.

4. What are units? Steve has 10. There are 43.6 of salt.
Numbers do not make sense if there is no unit.
A unit tells us what the number measures.
In science class there are NO NAKED NUMBERS- make them appropriate with a unit!

5. The International System of Units
ALL SCIENTISTS us the International System of Units.
We abbreviate it as SI.
Some good things about measuring in SI:
It is based on multiples of 10.
There are no fractions- we use decimals in the metric system.
Allows results to be easily shared between countries.

6. Who uses the SI system?
In everyday life, just about everyone except for US!
These countries do not use the metric system:
The United States of America
Liberia
Myanmar
ALL SCIENTISTS IN THE WORLD USE THE SI SYSTEM OF MEASUREMENT!

7. What are prefixes? Pre means “before”
A prefix is a small part of a word that comes before the word.
Metric prefixes equal a number.

8. Common Metric Prefixes
Symbol
Meaning
Giga- G
or 109
Mega- M
or 106
Kilo- K
1000
hecto- h
100
deca- da 10
deci- d
0.1 (one tenth)
centi- c
0.01 (one hundredth)
milli- m
0.001 (one thousandth)
nano- n
or 10-9

9. Adding prefixes
When we measure, we can add a prefix to change the value.
1 nanosecond = how many seconds?
Find nano- on your chart.
What does it mean?
1 nanosecond = 10-9 seconds
1 kilometer = 1000 meters
1 milligram = grams

10. Rules for writing metric symbols
Do not use a period.
7 s [not 7sec.]
Leave a space.
6 kg [not 6kg]
Do not add an s to the symbol.
10 Kilometers = 10 km [not 10 kms]
Do not capitalize, unless it is supposed to be capital.
Milliliter = mL [not Ml]
Do not use p for per.
miles per hour = mi/hr [not mph]

11. Write the correct units
mm = millimeter
mg = milligrams
L = liter
Mg = Megagram
m = meter
dam = decameter
g = gram cm = centimeters ns = nanosecond

12. Which number is bigger?
4 cm or 4 hm
10 km or 10 mm
12g or 12 kg

13. What will we measure? Length Mass Temperature Volume
Distance between two points.
Mass
Amount of material in an object.
Temperature
Amount of heat a material has.
Volume
Amount of space an object takes up.

14. What are BASE UNITS?
A base unit is the standard unit of measurement that we will use to measure.
We will add prefixes to the base units.

15. Measuring LENGTH
The SI base unit of measurement for length is the METER.
1 meter = 1m
Your desk is about one meter tall.
You can use a METRIC RULER or a METERSTICK to measure length.
Ribisi/Diozzi

16. Other units of length
If you wanted to measure between cities, you would use KILOMETERS.
A kilometer is equal to 1,000 meters.
If you wanted to measure small lengths, you would use a centimeter or a millimeter.
There are 100 centimeters in a meter.
Just like there are 100 cents in a dollar.
There are 1000 millimeters in a meter.

17. Practice!
How much carpet do you need to cover the floor in a room that measures 7 meters long and 5 meters wide?
L = 7 m
W = 5 m
A = L X W
A = 7 m X 5 m
A = 35m2

18. Measuring VOLUME of a liquid
The SI base unit of measurement for volume is the LITER.
1 Liter = 1L
You will use different units and tools to measure volume of a liquid or a solid.
You can use a GRADUATED CYLINDER to measure the volume of a liquid.

19. Graduated cylinders measure in mL or milliliters.
The plastic ring around a graduated cylinder prevents breaking.
To read a graduated cylinder:
Move to eye level.
Read the bottom of the meniscus.

20. VOLUME of a solid
If you are trying to find the volume of a solid, you cannot pour it into a graduated cylinder.
Methods:
Water displacement
Calculating volume

21. Water Displacement

22. What steps will you take to measure with water displacement?
Put water in the graduated cylinder.
Record the measurement.
Tilt the graduated cylinder to the side.
Gently lower the object into the graduated cylinder. (Make sure that the whole object is under water.)
Water & Object – Water = Object’s volume
REMEMBER 1 ml = 1 cm3 = 1 cc

23. Calculating Volume of a Block
To find the volume of a regular (block or box shaped) solid, you need to measure the length, width and height IN THE SAME UNIT and multiply these three numbers together. V= L X W X H
What is the volume of the black cube?
What is the volume of the bigger cube?
Volume = length X width X height
V = 3 cm X 2 cm X 2 cm
V = 12 cm3

24. Measuring MASS The SI base unit of measurement for mass is the GRAM.
1 gram = 1g
A paperclip is about 1 gram.
You can use a TRIPLE BEAM BALANCE or an ELECTRONIC SCALE to measure mass.

25. Other units of mass
If you wanted to measure large masses you would use KILOGRAMS.
1 Liter of pop has a mass of about 1 kilogram.
If you wanted to measure the mass of smaller objects, you would use milligrams or centigrams.
When have you heard someone say milligrams?

26. Ribisi/Diozzi

27. Measuring TEMPERATURE
The SI base unit of measurement for temperature is Kelvin (K).
A more common unit is DEGREES CELSIUS.
1 degrees Celsius = 1ºC
You can use a THERMOMETER to measure temperature.

28. Measuring TIME The SI base unit of measurement for time is the SECOND.
1 second = 1s
We will use a STOPWATCH to measure time in science class.

29. Write this chart: Find the unit you are starting with.
kilo
hecto
deca
BASE UNIT
deci
centi
milli k h da
gram (g)
meter ( m)
liter (L) second (s) d c m
1000
100 10
0.1
0.01
0.001
103
102
101
10-1
10-2
10-3
Find the unit you are starting with.
Find the unit you want to change to.
Count the number of spaces you have to move.
Which way did you move?
Move the decimal in that direction that number of spaces.

30. How can we remember the order of the chart?
Kids Have Dropped OVER Dead Converting Metrics
Kilo Hecto Deca OVER Deci Centi Milli
meter
liter
gram
What is your mnemonic device?