CHAPTER 1, SECTION 2 Standards of Measurement

IS AN EXACT QUANTITY THAT PEOPLE AGREE TO USE TO COMPARE MEASUREMENTS WHY WOULD A STANDARD BE IMPORTANT? Standard

Measurement Systems For a measurement to make sense it must include two things…  Number  Unit

English system International System (SI) Commonly used in the United States Examples: pound, gallon, foot Harder to use because it does not rely on bases of ten Used all over the world Is an improved version of the metric system Uses base units such as meter, Liter, gram Easy to use because it is based on multiples of ten!!! Measurement Systems

SI Base Units (pg. 15) Length Mass Time Electric current Temperature Amount of substance Intensity of light Meter (m) Kilogram (kg) Second (s) Ampere (A) Kelvin (K) Mole (mol) Candela (cd)

*meters can be replaced with any other unit of measurement Mega (M) Kilo (k) Deci (d) Centi (c) Milli (m) Micro (  ) Nano (n) Pico (p) 1 Megameter = meters 1 Kilometer = 1000 meters 10 Decimeters = 1 meter 100 Centimeters = 1 meter 1000 Millimeters = 1 meter Micrometers = 1 meter Nanometers = 1 meter Picometers = 1 meter

THERE WILL BE SIMILAR PROBLEMS TO THIS ON THE TEST Conversion Example Problems

Homework Convert s to ms g to kg dm to m g to mg m to Mm µs to s 7. 2 m to cm ng to g s to ps mL to kL

Measuring Volume The amount of space occupied by an object is called its volume. Volume can be measured two ways: 1. If you want to know the volume of a solid rectangle you measure its length, width, and, height and multiply the three numbers and their units together (V = 1 x w x h).  The volume would then be expressed in cubic ___meters, for example cm In measuring a liquid’s volume, you would use a graduated cylinder. When measuring an irregular shaped object you would measure the water displaced in a graduated cylinder.  The most common units for expressing liquid volumes are liters and milliliters. Sometimes, liquid volumes such as doses of medicine are expressed in cc’s. 1 cm 3 = 1 mL = 1 cc

Measuring Matter Mass is a measurement of the quantity of matter in an object. Mass can be measured using a triple beam balance or any type of digital scale. The unit usually used for mass is the gram.

Density The mass and volume of an object can be used to find the density by using the formula D = m/v Density is the mass per unit volume of a material The unit of measurement for density is a derived unit. A derived unit is a combination of base units For example, g/cm 3 or g/mL

A block of aluminum occupies a volume of 15.0 mL and has a mass of 40.5 g. What is its density?

A rectangular block of copper metal has a mass of 1896 g. The dimensions of the block are 8.4 cm by 5.5 cm by 4.6 cm. From this data, what is the density of copper?

The volume of a solution was measured in a graduated cylinder (shown above). If the mass of solution is measured to be grams, what is the density of the solution?

28.5 g of iron shot is added to a graduated cylinder containing 45.5 mL of water. The water level rises to the 49.1 mL mark, From this information, calculate the density of iron.

I threw a plastic ball in the pool for my dog to fetch. The mass of the ball was 125 grams. What must the volume be to have a density of g/mL?

An ice cube measuring 5.80 cm by 5.80 cm by 5.80 cm has a density of g/mL. What is the mass?

Time Time is the interval between two events. The SI unit for time is the second.

Temperature Celsius On the Celsius scale, the freezing point of water is 0  C, and the boiling point of water is 100  C. Kelvin The SI unit of temperature is the kelvin (K). Zero on the Kelvin scale (0 K) is the coldest possible temperature, also known as absolute zero. Absolute zero is equal to -273  C which is 273  below the freezing point of water. Kelvin temperature can be found by adding 273 to the Celsius reading. So, on the Kelvin scale, water freezes at 273 K and boils at 373 K. Fahrenheit The temperature measurement you are probably most familiar with is the Fahrenheit scale Human Body 98.6  F and Freezing point of water 32  F.