8/2. Why do we need this? Scientists need standard units of measurement so that their work can be...
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Transcript of 8/2. Why do we need this? Scientists need standard units of measurement so that their work can be...
![Page 1: 8/2. Why do we need this? Scientists need standard units of measurement so that their work can be reproduced by other scientists. (previously known.](https://reader035.fdocuments.in/reader035/viewer/2022070403/56649f305503460f94c4b93e/html5/thumbnails/1.jpg)
MEASUREMENT/SI UNITS
8/2
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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)
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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
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![Page 5: 8/2. Why do we need this? Scientists need standard units of measurement so that their work can be reproduced by other scientists. (previously known.](https://reader035.fdocuments.in/reader035/viewer/2022070403/56649f305503460f94c4b93e/html5/thumbnails/5.jpg)
![Page 6: 8/2. Why do we need this? Scientists need standard units of measurement so that their work can be reproduced by other scientists. (previously known.](https://reader035.fdocuments.in/reader035/viewer/2022070403/56649f305503460f94c4b93e/html5/thumbnails/6.jpg)
How Do I Remember It?
King Henry Died By Drinking Chocolate Milk
Kilo, Hecto, Deca, BASE, Deci, Centi, Milli
B = Base Unit (No Prefix)
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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!!!
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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
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Triple Beam Balance
http://www.wisc-online.com/objects/index_tj.asp?objID=GCH202
What are the units?
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Graduated Cylinder
http://www.uwplatt.edu/chemep/chem/chemscape/labdocs/catofp/measurea/volume/gradcyl/gradcyl.htm
What are the units?
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Rounding
What does it mean to round to the nearest tenth?
Hundredth?
Thousandth?