Notes: Measurement (1.2-1.3)

There are two systems of measurement that are used today. . . --METRIC/ “Système Internationale” (world-wide) --STANDARD / “Customary” (just USA) King Henry I created the “yard” by the length between fore-finger and nose . The French later wanted something easier to work with, and, that everyone could use, based on units of 10. Everyone went along with the new, logical idea eventually, except the USA.

The METRIC SYSTEM (SI) is the easiest to use, because you can convert units by multiplying or dividing by “10” . . (Otherwise, you would have to memorize quantities like carats, stones, hands, furlongs, miles, yards, pints, inches, feet, gallons, quarts, ounces, pounds, tons, cords, and many other units that have no predictable relationship with each other. )

In Metrics, the basic units used are: METER (for length or distance) LITER (volume) GRAM (mass or) weight) A baseball bat is about one meter long. We usually buy “2 liter” bottles of soda. A dollar bill is about one gram.

This step chart is helpful when converting Metric Units This step chart is helpful when converting Metric Units. For instance, how many milligrams is equal to 5.26 hectograms? Or left BIG Unit = 1 METER, LITER, GRAM Right, or SMALL

What is appropriate? When drawing blood, would you rather have. . 4 Liters 4 Deciliters 4 Milliliters drawn? (Hint: Think about drinking a 2 liter bottle of soda)

What is appropriate? Would you rather measure your stack of homework in. . . 5 dm 5 mm 5 cm (Hint: What does a meter stick look like? )

Practice These: 1 2 3

Definitions . . . Mass is how much matter is present in a substance. Weight is how hard gravity is pulling on that mass. Volume is capacity, or how much matter something is able to hold. V = l x w x h (or) V = ml and 1ml = 1 gram

More info on the world of liquids… Liquid measure in metrics is based on the LITER. -- Milliliters in smaller quantities can be accurately measured with a graduated cylinder. -- Water is electrically attracted to the sides of the narrow cylinder, so the surface of the water level is bent into a meniscus. -- You always need to measure liquid at the bottom of the meniscus mark.

1cc (cubic centimeter) = 1 ml = 1cc (cubic centimeter) = 1 gram of water! Graduated Cylinders and liquids can also be used to measure the volume of non-liquid objects. This method is called displacement (try the picture) How much does the water go up?

. . Some more advice about linear measuring. . . Occasionally, you might read a thermometer or ruler level that does not land exactly on a printed mark. In this case, measure exactly to the mark just lower than the meniscus, and add a “5” (Practice with this

Try these also. . .

DENSITY is one of the most important themes in earth science! It is the amount of matter that occupies a given space. Density can be calculated by D = m/v. Anything with a density less than one is a “floater”, and greater than one is a “sinker” Denser things are heavier, since they’re pulled on harder by gravity

The earth is layered according to density. . . For instance, a 1 m3 box of beans is much less dense than the same box of water (less “crowded”, more space between particles)

A rock was dropped into a graduated cylinder A rock was dropped into a graduated cylinder. What was it’s density if it had a mass of 90 g? D = m/v Water displaced 70 cm3 90g / 70cm3 D = 1.286 g / cm3 Remember – 1 ml = 1 CC (cc = 1 cubic centimeter)

YouTube has some wonderful videos for explaining the details www.videochemistrytextbook.com https://www.youtube.com/watch?v=7tVebi3TSsg https://www.youtube.com/watch?v=HZ9weUkSdoY

A block of wood has the following dimensions A block of wood has the following dimensions. What is it’s density, if it has a mass of 150g? Is it a floater or a sinker? D = m/v D = 150g/v V = L x W x Depth 9 x 10 x 3 =270 in cubed ANSWER: D=150G/270 Inch cubed = 0.55 g/inch cubed

Showing Measurement Graphically The best science experiments are ones that have results which can be measured. The “cause” = independent variable The “effect” = dependent variable (Sometimes there are more than one) INDEPENDENT The scientist sets it up, the control DEPENDENT The scientist doesn’t know what will happen, the result

In each example, which is the independent, and which is the dependent variable? Rat poison__, # of rats__ Weight of person__, calorie intake__ Plant growth__, hours of daylight__ Cost of insurance__, driving record__ Independent variable causes a change in the Dependent Variable, and it isn't possible that Dependent Variable could cause a change in Independent Variable.

In a lab report, Independent Variables are placed to the left and the bottom

State how many I and D variables each experiment appears to have…

GRAPHING STYLES for representing data Bar Graph – Compares amounts. X-axis has words/labels Line graph – Tracking results over time. X-axis has units of time. Scatter plot – Tracking relationships between the cause and the effect. A pattern of dots is called a “correlation”. Histogram – Compares patterns of amounts. X-axis has numbers