1. SI – International System of Units
SI - (AKA International System of Units or S.I.) is a measuring system based on units of 10.
Math – the language of science
Units in the S.I. are:
meter (m), which is used for measuring length.
liter (l), which is used to measure volume. *
gram (g), which is used to measure mass.

2. SI (metric) prefixes Kilo (k) Hecto (h) Deka (de) or deca (da)
Base Unit
(m, l, or g)
Deci
(d)
Centi
(c)
Milli
(m)
1000
100 10 1
0.1
0.01
.001
1000/1
100/1
10/1
1/10
1/100
1/1000

3. STOP DO NOT WRITE UNTIL I TELL YOU TO 
The three prefixes that we will use the most are:
kilo
centi
milli
kilo
hecto
deca
Base Units
meter
gram
liter
deci
centi
milli

4. These prefixes are based on powers of 10. What does this mean?
From each prefix every “step” is either:
10 times larger or
10 times smaller
For example
Centimeters are 10 times larger than millimeters
1 centimeter = 10 millimeters
kilo
hecto
deca
Base Units
meter
gram
liter
deci
centi
milli

5. An easy way to move within the metric system is by moving the decimal point one place for each “step” desired (swoop method)
Example: change meters to centimeters
1 meter = 10 decimeters = 100 centimeters or
1.00 meter = 10.0 decimeters = 100. centimeters
kilo
hecto
deca
meter
liter
gram
deci
centi
milli

6. If you move to the left in the diagram, move the decimal to the left
If you move to the right in the diagram, move the decimal to the right
kilo
hecto
deca
meter
liter
gram
deci
centi
milli

7. YES WRITE THESE NOTES: Summary
Base units in the SI (metric system) are meter, liter, gram
Metric system is based on powers of 10
For conversions within the SI, each “step” is 1 decimal place to the right or left
Using the diagram below, converting to the right, moves the decimal to the right and vice versa
kilo
hecto
deca
BASE UNITS
meter
liter
gram
deci
centi
milli

8. Practice problems:

9. Base SI Units
Quantity
Unit
Symbol
Length
meter m
Mass
kilogram kg
Temperature
kelvin K
Time
second s
Amount of Substance
mole
mol
Luminous Intensity
candela cd
Electric Current
ampere a

10. Other - SI Unit Prefixes
Name
Symbol
giga- G
109
mega- M
106
kilo- k
103
deci- d
10-1
centi- c
10-2
milli- m
10-3
micro- μ
10-6
nano- n
10-9
pico- p
10-12

11. Derived SI Units (examples)
Quantity
unit
Symbol
Volume
cubic meter m3
Density
kilograms per cubic meter
kg/m3
Speed
meter per second
m/s
Newton
kg m/ s2 N
Energy
Joule (kg m2/s2) J
Pressure
Pascal (kg/(ms2) Pa

12. Units for Volume 1cm3= 1mL m3 cm3 L mL
When do you use m3 ? irregular objects?
1cm3= 1mL

13. Tools for measuring:

14. 1. Using a Ruler Centimeters and Millimeters

15. How to use a metric ruler
1. Begin on the 1cm mark and make your
recording.
2. Subtract 1 from the number your recorded
to get your answer. For example:
1.5cm cm = 0.5 cm
Make sure you include 1 digit after the decimal. This is usually an estimate.

16. Let’s Practice
3.85 cm cm = cm

17. Centimeters are 10 times larger than millimeters so it takes more millimeters for the same length
1 centimeter = 10 millimeter
4 00
411
1 mm 40 41
1 cm

18. 2. Graduated cylinder How to read a graduated cylinder
1. Place the graduated cylinder on a flat
surface.
2. Read from the bottom of the meniscus
(bubble) at EYE LEVEL.
3. Again you want to estimate.

19. Graduated Cylinder - Meniscus

21. 3. Triple – beam balance How to use a triple-beam balance
1. Move all sliders/masses to the left. 2. Check to see if the mark on the moving arm lines up with the 0 on the balance. 3. Place specimen on pan then move the sliders until the marks line up at 0.

22. Let’s Practice

23. 4. Digital Balance How to use a digital balance
1. Place the electronic balance on a flat, stable surface indoors.
Press the "ON" button and wait for the balance to show zeroes on the digital screen.
Use a container for your object to be massed (never place directly on the balance).
Press the "Tare" or "Zero" button to automatically deduct the weight of the container from future calculations. The digital display will show zero again, indicating that the container's mass is stored in the balance's memory.
Carefully add the substance to the container. Ideally this is done with the container still on the platform, but it may be removed if necessary. Avoid placing the container on surfaces that may have substances which will add mass to the container such as powders or grease.
Place the container with the substance back on the balance platform if necessary and record the mass as indicated by the digital display

24. Picture here,..

25. Why do we use the SI/Metric System?
To making accurate and precise measurements.

26. Percent Error
% Error= |experimental –accepted| x100
accepted value