Day 3

January 17, 2013

Agenda Safety Quiz Practice News Article (if needed) English to English Conversions SI and Metric System English vs. Metric

Practice Metric to Metric

Practice

English to English

Conversions

English to English Convert 86 inches to feet

English to English Convert .3 feet to miles

English to English Convert 74 miles to yards

Converting English

to Metric

Metric System This can seem like another language….

Who Doesn’t Use Metric?

USA

Myanmar

Liberia

Metric System SI Base Units

Meter (m) Kilogram (kg) Second (s) Kelvin (K) Ampere (A) Mole (mol) Candela (cd)

Meter (m) Base unit for distance Originally 1/10,000,000 of the distance

from equator to the pole Once defined by the length of a bar of

metal Now- the distance light travels in a

vacuum in 3x10-9s

Kilogram (kg) SI base unit for mass A platinum-iridium bar maintained by the

International Bureau of Weights & Measures near Paris, France

By design, approximately the mass of a liter of water

Second (s) SI base unit for time Was defined as 1/86,400 mean solar day,

but it wasn’t constant Now defined as 9,192,631,770 vibrations

(cycles) of Cesium-133

Kelvin (K) SI base unit for temperature Previously called degrees Kelvin (0K) In 1967 defined triple point (the exact

temperature at which water exists as gas, liquid and solid) of water as 273.16K

00C equals 273.16K

Ampere (A) SI base unit for electric current Defined as :The amount of current that will

produce a force of .2micronewtons between 2 parallel conductors, (infinitely long and having a negligible cross section) one meter apart in a perfect vacuum.

Mole (mol) SI base unit for the amount of a

substance. The actual number of atoms or molecules in an object.

Official definition is that one mole of any substance contains just as many elementary particles as there are in Carbon-12.

Candela (cd) SI base unit for the intensity of light Originally it represented the intensity of an actual

candle made from whale tallow at a specified rate in grains/hr.

Replaced with a definition in terms of light produced by an incandescent bulb

Changed again to define the intensity of 1/600000m2 of a black-body at a temperature of 2042K

Not happy with that - changed to represent the intensity of a single-frequency light at a frequency of 540THz (green) with a power of 18.3988mW

English to Metric Convert 14 inches to meters

English to Metric Practice, Practice, Practice, Practice,

Practice, Practice, Practice, Practice, Practice, Practice,

Metric to Metric

Conversion

Metric to Metric Conversions within the Metric System Start by setting up the relationship

between the prefixes:

k (unit) d c m µ n

Metric to Metric Then add the decimal places between the

prefixes this will be our template: 3 1 1 1 3 3k (unit) d c m µ n

Metric to Metric The units that we’ll be using are:

gram (g), liter (L) and meter (m)

Metric to Metric Once the template is constructed it’s just a

matter of moving the decimal point from an original position to the required new prefix.

Metric to Metric Convert 58cm to km

1. Place the decimal point in the correct position (if not already placed)

58cm = 58.0cm

Metric to Metric 2. From the position in the template we

know that the decimal point is going to move to the left. (the position of the prefix c to the prefix k)

3 1 1 1 3 3k (unit) d c m µ n

Metric to Metric 3. Add up the total number of decimal

places between the prefix c and the prefix k. Then move the decimal point that number of places. (5)

3 1 1 1 3 3k (unit) d c m µ n

Metric to Metric 4. Install zeros to fill the vacancy between

the beginning number and the new number.

58.0cm becomes .00058km

Metric to Metric The numbers involved NEVER change!

The position of the decimal point and the number of zeros DOES change!

PRACTICE!!!