CHEMISTRY (cid:55)(cid:75)(cid:72)(cid:85)(cid:72)(cid:3)(cid:68)(cid:85)(cid:72)(cid:3)(cid:20)(cid:15)(cid:19)(cid:19)(cid:19)(cid:3)(cid:80)(cid:76)(cid:79)(cid:79)(cid:76)(cid:80)(cid:72)(cid:87)(cid:72)(cid:85)(cid:86)(cid:3)(cid:298)(cid:80)(cid:80)(cid:299)(cid:3)(cid:76)(cid:81)(cid:3) 1 meter There are 1,000 meters in a (cid:78)(cid:76)(cid:79)(cid:82)(cid:80)(cid:72)(cid:87)(cid:72)(cid:85)(cid:3)(cid:298)(cid:78)(cid:80)(cid:299)(cid:17) Doctors measure your height in the standard unit of inches Scientists measure height in the metric unit of centimeters Unit of Measurement Abbreviation millimeter centimeter meter kilometer mm cm m km Things You Might Measure With This Unit ant small button or end of an eraser hamster length of your foot or the length of a gecko lizard distance between your classroom and the lunchroom or the length of a Komodo dragon or a whale distance of a marathon or the distance between two cities Measurement Y Scientists use the metric system People can describe the world in many ways They can say how big something is how much it weighs or how hot it feels They can use measurements to describe these things to measure distance and length They measure distance and length using a metric ruler tape measure or other special tools A meter is a specific unit of measurement A meter can be broken down into smaller parts called centimeters and millimeters There are (cid:20)(cid:19)(cid:19)(cid:3)(cid:70)(cid:72)(cid:81)(cid:87)(cid:76)(cid:80)(cid:72)(cid:87)(cid:72)(cid:85)(cid:86)(cid:3)(cid:298)(cid:70)(cid:80)(cid:299)(cid:3)(cid:76)(cid:81)(cid:3)(cid:20)(cid:3)(cid:80)(cid:72)(cid:87)(cid:72)(cid:85)(cid:3)(cid:298)(cid:80)(cid:299)(cid:17)(cid:3) R T S I M E H C S I T A H W 8
CHEMISTRY Unit of Measurement Abbreviation kilogram gram milligram kg g mg Things You Might Measure With This Unit yourself or a dog a bag of apples or a box of cookies a paper clip or a baby tooth Scientists use grams or milligrams to measure the weight of something Scales are instruments used to measure weight Scientists use scales that weigh in kilograms grams or milligrams What’s the Difference Between Mass and Weight Weight is the measure of how strongly gravity pulls on matter Mass is the measure of how much matter an object has If you were to go to the Moon your weight would change because the pull of gravity on Earth is stronger than on the Moon Your mass would not change because you would still have the same amount of matter This scale measures in the standard unit of pounds or the metric unit of kilograms W H A T I S C H E M I S T R Y 9
CHEMISTRY 10 CHEMISTRY W H A T I S C H E M I S T R Y Scientists measure temperature using the Celsius temperature scale The freezing and boiling points of (cid:90)(cid:68)(cid:87)(cid:72)(cid:85)(cid:3)(cid:76)(cid:86)(cid:3)(cid:87)(cid:75)(cid:72)(cid:3)(cid:69)(cid:68)(cid:86)(cid:76)(cid:86)(cid:3)(cid:73)(cid:82)(cid:85)(cid:3)(cid:38)(cid:72)(cid:79)(cid:86)(cid:76)(cid:88)(cid:86)(cid:3)(cid:298)(cid:131)(cid:38)(cid:299)(cid:17)(cid:3) (cid:58)(cid:68)(cid:87)(cid:72)(cid:85)(cid:3)(cid:73)(cid:85)(cid:72)(cid:72)(cid:93)(cid:72)(cid:86)(cid:3)(cid:68)(cid:87)(cid:3)(cid:19)(cid:131)(cid:38)(cid:3)(cid:68)(cid:81)(cid:71)(cid:3)(cid:69)(cid:82)(cid:76)(cid:79)(cid:86)(cid:3)(cid:68)(cid:87)(cid:3) (cid:20)(cid:19)(cid:19)(cid:131)(cid:38)(cid:17)(cid:3)(cid:36)(cid:81)(cid:3)(cid:68)(cid:89)(cid:72)(cid:85)(cid:68)(cid:74)(cid:72)(cid:3)(cid:85)(cid:82)(cid:82)(cid:80)(cid:3)(cid:87)(cid:72)(cid:80)(cid:83)(cid:72)(cid:85)(cid:68)(cid:87)(cid:88)(cid:85)(cid:72)(cid:3)(cid:76)(cid:86)(cid:3) (cid:68)(cid:69)(cid:82)(cid:88)(cid:87)(cid:3)(cid:21)(cid:19)(cid:131)(cid:38)(cid:17)(cid:3)(cid:3)(cid:3) Another way of measuring temperature is to use the Kelvin scale The lowest possible temperature (cid:71)(cid:72)(cid:87)(cid:72)(cid:85)(cid:80)(cid:76)(cid:81)(cid:72)(cid:86)(cid:3)(cid:87)(cid:75)(cid:72)(cid:3)(cid:46)(cid:72)(cid:79)(cid:89)(cid:76)(cid:81)(cid:3)(cid:298)(cid:46)(cid:299)(cid:3)(cid:86)(cid:70)(cid:68)(cid:79)(cid:72)(cid:17)(cid:3)(cid:55)(cid:75)(cid:76)(cid:86)(cid:3)(cid:76)(cid:86)(cid:3) (cid:19)(cid:3)(cid:46)(cid:3)(cid:82)(cid:85)(cid:3)(cid:293)(cid:21)(cid:26)(cid:22)(cid:131)(cid:38)(cid:17)(cid:3)(cid:36)(cid:69)(cid:86)(cid:82)(cid:79)(cid:88)(cid:87)(cid:72)(cid:3)(cid:87)(cid:72)(cid:80)(cid:83)(cid:72)(cid:85)(cid:68)(cid:87)(cid:88)(cid:85)(cid:72)(cid:86)(cid:3) are temperatures measured in the Kelvin scale Thermometers display temperature using the standard Fahrenheit scale and the metric Celsius scale distance DISS-tuhnss the amount of space between two places length lengkth the distance from one end of something to the other measure MEZH-ur to find out the size capacity weight etc of something metric system MET-rik SISS-tim a system of measurement based on counting by 10’s temperature TEM-put-uh-chur the degree of heat or cold in something
11 CHEMISTRY A T O M S A N D E L E M E N T S CHEMISTRY Atoms are the building blocks of all matter Atoms are very small Many atoms put together make up everything in the world Atoms are so small that you cannot see an individual atom without a special microscope All atoms are made of the same basic parts Putting these parts together in different ways by scientists or in nature causes the traits of the atom to change Atoms and Elements Scientists use electron microscopes to give them an idea of what atoms look like
