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Scientific Measurement. A review…. The common language of measurements in science used all over the world is the metric system. The metric system is a decimal system or a system based on ten. Length. The meter is the basic unit length. The tool that we use most often is the meter stick.
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Scientific Measurement A review…
The common language of measurements in science used all over the world is the metric system. • The metric system is a decimal system or a system based on ten.
Length The meteris the basic unit length. The tool that we use most often is the meter stick. Longer distances would be measured in kilometers.
Volume • Volume is the amount of space something takes up • The basic unit of measure for volume is Liters. • Volume conforms to the container that contains it (shape) • The tool that we use to measure liquid volume is called the graduated cylinder. We measure from the bottom of a line called the meniscus. • the meniscus results from water being pulled down by other water molecules – cohesion– and from water being attracted to the side of the container -- adhesion
Liquid Volume is measured in milliliters (mL) or liters (L) • Solid Volume is measured in cubic centimeters (cm3) • For Regular Solid Volume: Length X Width X Height • 2cm X 3 cm X 2cm = 12cm3 • For Irregular volume: (no regular shape) you must use the volume displacement method.
Volume Displacement Method • place a known value in a graduated cylinder ( 7 ml) • place the irregular object into the graduated cylinder • measure the displacement of volume ( where did the liquid move up to) ( 9ml) • Subtract the original volume from the new volume ( 2ml) • Calculate the volume of the object as 2cm3 ( because it is a solid, not liquid)
Mass • the amount of matter in an object (different from weight – weight depends on gravity, mass does NOT!) • The gram is the basic unit of measure • The tools that we use are the triple beam balance, electronic balance, or a scale
Electronic Balance – more precise Triple Beam Balance – counter balance system
Basic Safety • DRESS for lab – closed toed shoes, wear apron, wear eye protection, pull back hair, remove jewelry, keep loose clothes secured (observe ALL above until lab is completely cleaned up for the day…) • Read lab directions IN ADVANCE!!! • Listen to directions and ask if unsure • Stay in lab area assigned • FOLLOW DIRECTIONS, don’t go out on own • NEVER EAT OR DRINK in the lab • If have an accident, spill or breakage, report it immediately and replace needed equipment • CLEAN LAB AREA before leave USE COMMON SENSE!!!