The Metric System. Why do I need to learn and be able to use the metric system?. Everyday Metric. http://www.nisenet.org/viz_lab_image_scaler. Standard International Units (SI). Metric Conversions. Metric Prefix Table Prefix Symbol Multiplier Exponential giga G 1,000,000,000 10 9
Why do I need to learn and be able to use the metric system?
Metric Prefix Table
giga G 1,000,000,000 109
mega M 1,000,000 106
kilo k 1,000 103
Base Unit 1 100
deci d 0.1 10¯1
centi c 0.01 10¯2
milli m 0.001 10¯3
micro µ 0.000001 10¯6
nano n 0.000000001 10¯9
pico p 0.000000000001 10¯12
Because it is being used now!
Untrathin glass treatment
Nanocrystals are used in photovoltaic cells as well as drug research
Using nanotechnology, Cornell scientists created a fabric that can detect biohazards like E. coli and other pathogens.
Stain repellent clothing
Antibacterial paint in hospitals
Follow these steps to set up a dimensional analysis problem
1. List all given information with the correct units.
2. Write down what you are trying to determine along with the correct unit.
3. List the conversion factors needed to solve the problem.
4. Write your given information as a fraction with the correct units.
5. Set up a chain of “fractions” (conversion factors) to convert from the given units to the desired units. To cancel out the original unit, place that same unit in the denominator where it will cancel out later.
6. Verify that all units cancel out except the units of the desired answer.
7. Do the math and record the final answer to the correct number of significant digits and in proper scientific notation. Include the correct units.
8. Circle your final answer.
1 l 109 nm l 1m
= 1.5 x 10-6 cm
NASA: Human error caused loss of Mars orbiter
November 10, 1999
WASHINGTON (AP) -- Failure to convert English measures to metric values caused the loss of the Mars Climate Orbiter, a spacecraft that smashed into the planet instead of reaching a safe orbit, a NASA investigation concluded Wednesday.
The Mars Climate Orbiter, a key craft in the space agency's exploration of the red planet, vanished after a rocket firing September 23 that was supposed to put the spacecraft on orbit around Mars.
Which is correct? 66 ml, 66.0 ml, 66.1 ml, 67 ml, 67.0 ml, 67.5 ml
There are three rules on determining how many significant figures are in a number:
Identify the number of significant figures:
1) 3.0800 2) 0.00418
3) 7.09 x 10¯5 4) 91,600
5) 0.003005 6) 3.200 x 109
7) 250 8) 780,000,000
9) 0.0101 10) 0.00800
RULE: When multiplying or dividing, your answer may only show as many significant digits as the multiplied or divided measurement with the least number of significant digits.
Example: When multiplying 22.37 cm x 3.10 cm x 85.75 cm = 5946.50525 cm3
22.37 shows 4 significant digits.
3.10 shows 3 significant digits.
85.75 shows 4 significant digits.
RULE: When adding or subtracting your answer can only show as many decimal places as the measurement having the fewest number of decimal places.
Example: When we add 3.76 g + 14.83 g + 2.1 g = 20.69 g
3.76 shows 2 decimal places
14.83 shows 2 decimal places
2.1 shows 1 decimal place
Solve the following problems and report answers with appropriate number of significant digits.
1) 6.201 cm + 7.4 cm + 0.68 cm + 12.0 cm = ?
2) 1.6 km + 1.62 m + 1200 cm = ?
3) 8.264 g - 7.8 g = ?
4) 10.4168 m - 6.0 m = ?
5) 12.00 m + 15.001 kg = ?
6) 131 cm x 2.3 cm = ?
7) 5.7621 m x 6.201 m = ?
8) 20.2 cm divided by 7.41 s = ?
9) 40.002 g divided by 13.000005 ml = ?