Embed Size (px)
Citation preview
MEASUREMENT/SI UNITS
8/2
SI Units
Why do we need this? Scientists need standard units of
measurement so that their work can be reproduced by other scientists. (previously known as the metric system)
Base Units
There are seven base units in SI.
A base unit –has no prefix (what is a prefix) Exception –mass (kg)
So what is expressed in base units? Time Length Mass Temperature
How Do I Remember It?
King Henry Died By Drinking Chocolate Milk
Kilo, Hecto, Deca, BASE, Deci, Centi, Milli
B = Base Unit (No Prefix)
Let’s Practice Converting Between Units
1 mL KL 45 g cg 0.26 decaseconds deciseconds 410 Km cm
All you are doing is moving the decimal!!!
How do I measure things in chemistry?
To measure mass you will use a triple beam balance. Your METRIC units will be in grams.
To measure liquids or volume, you will use a
graduated cylinder. Your METRIC units will be in
milliliters (mL) . To measure the length, width, or height of
an object, you will use a ruler. Your metric units will be
in millimeters, centimeters, or meters. What is the difference between these units?
The metric unit for temperature is Kelvin (K) What would I use? C + 273
Triple Beam Balance
http://www.wisc-online.com/objects/index_tj.asp?objID=GCH202
What are the units?
Graduated Cylinder
http://www.uwplatt.edu/chemep/chem/chemscape/labdocs/catofp/measurea/volume/gradcyl/gradcyl.htm
What are the units?
Rounding
What does it mean to round to the nearest tenth?
Hundredth?
Thousandth?
