4.1 use basic scientific measurements and measurement tools

The SI base units for mass, length and time are

kilogram, meter, second

International System of Units ( SI Units)

a system of physical units based on the meter, kilogram, second, celcius, and kelvin together with a set of prefixes to indicate multiplication or division by a power of ten

* SI units are also used to measure volume.(liter)

7 base units

Kilogram, meter, second, mole, kelvin, candela, ampere

Meter (M)

instrument for measuring length

* Abbreviation M

kilogram (kg)

*SI unit for mass

*measures mass

Second

SI base unit for time

Ampere

*unit of electric current

* measures electrical current

Kelvin (K)

SI unit for temperature

Kelvin = Celsius + 273

mole (mol)

the SI base unit used to measure the amount of a substance

* measures amount of a substance.

Candela ( cd)

the standard unit of luminous intensity

* measures luminous intensity

Length

Distance between two points, measured in meters.

metric ruler/meter stick

instrument used to measure length .

( si uses the meter end of the ruler)

The SI base unit for volume

liter (L)

Surveyor's wheel( measuring wheel)

Used to determine longer or along nonlinear path.

Measuring tape

Measures length in inches or centimeters.

* inches are divided into 1/16th of an inch and centimeters are divided into millimeters.

. measures linear distances

linear distance

how far across the earth a person, an idea, or a product travels

Nonlinear distances

Mass

*A measure of the amount of matter in an object

Volume

The amount of space an object takes up or occupies.

* Volumes are measured by using glassware or plasticware.( in liters)

graduated cylinder

*used to measure the volume of a liquid.

* used when measurements does not need to be precise.

measures volumes ranging from 10ml to 1000 ml or 1 liter.

volumetric flask

*used for making liquid solutions of precise volumes.

* each volumetric flask is calibrated for a single volume

*The most accurate way to measure large volumes of liquid.

Pipettes

measures small amounts of liquids accurately

Graduated pipettes

* delivers measurements ranging from 0.1 to 25 ml and can easily dispense liquids in small increments

*Different Volumes

Two Types = Mohr and Serological

*Consist of a long tube with a series of graduations or marks to indicate different calibrated volumes.

Volumetric pipettes

* are preferred for high precision work.

*calibrated to deliver accurately a fixed volume of a dilute aqueous solution.

*best used to measure small amounts of liquid.

Meniscus

the curve at a liquid's surface by which one measures the volume of the liquid

* can be concave, convex or flat depending on the properties of the liquid.

concave

curving inward ( upward)

Convex

curved outward ( downward).

SI Unit Prefixes

*Used to change SI units by powers of 10

*Kilo, Hecto, Deka, BASE, deci, centi, milli (acronym) King Henry Died By Drinking Chocolate Milk

Kilo (1000)

Value of prefix= One thousand/1000

Abbreviation- km= kilometer

Hecta (100)

Value of prefix= One hundred/ 100

Abbreviation- hm= hectameter

Deca( 10)

Value of prefix= Ten

Abbreviation- dam= decameter

Base SI Units (1)

Gram, liters, meter

deci (0.1)

Value of prefix=

Abbreviation

milli (0.001)

Value of prefix= One thousandth

Abbreviation- mm= millimeter

centi (0.01)

Value of prefix=

Abbreviation- cm=centimeter

micro

Value of prefix= One millionth

Abbreviation- = micrometer

Kilo, hecta, deca,

Multiply by 10

Centi , milli deci

Divide by 10

dimensional analysis

a technique of problem-solving that uses the units that are part of a measurement to help solve the problem

measuring instrument for mass

Triple beam balance and electronic balance.

Triple beam balance

instrument used to measure mass in grams

* measures in 1, 10, 100 gram increments.

Electronic balance

measures mass of an object in grams

analytical balance

*Measures small amounts of materials

*Used measure the mass of substances to +/-0.0001 precision.

*often called a "lab balance" designed to measure small mass in the sub-milligram range. The measuring pan of an analytical balance (0.1 mg or better) is inside a transparent enclosure with doors so that dust does not collect and so any air currents in the room do not affect the balance's operation

Sound waves or sonar

Are used to map ocean depths

Beams of light or electromagnetic radiation

Measures the distance planets.

The speed of sound

1500 meters per second

Distance equals

speed of sound x time