3. How many ounces are there in 62.3ml? Warm-Up # 3 1. Convert 600 g to kg 2. How many miles are in 5.00 km? 3. How many ounces are there in 62.3ml?

Measurements are fundamental to science Measurements may be: a. Qualitative b. Quantitative

Measurements Qualitative Measurement: is a non- numerical measurement Example: The solution turned brown when ammonia was added to iron (III) chloride

Quantitative Measurements Quantitative Measurements: consist of two parts a. A number b. A scale (or unit) Example: The rock has a mass of 9.0 kg

SI Units and Prefixes The SI system used prefixes “Kilo-” means 1000; symbol is k “Hecto” means 100; symbol is h “Deca” mean 10; symbol is da “Base” means 1; meter/liter/gram “Deci-” means 0.1; symbol is d “Centi-” means 0.01; symbol is c “Milli-” means 0.001; symbol I m King Henry Died By Drinking Chocolate Milk

Length- is the distance between two points The SI unit of length is the meter (m) Devices used to measure length: Rulers, Tape Measurers, and Meter Sticks

Volume (V) Volume- is the amount of space an object occupies Volume of a cube is length * width * height Volume of a cylinder is V=πr2h The SI unit for volume is m3(Cubic meter ) Other units for V: mL, cm3, dm3 The Liter (L) is also used for volume of liquids

Volume Continued Conversions for volume: 1 dm3 (decimeter cubed ) = 1 L 1 cm3 = 1 mL (milliliter)= 1 cc Devices Used to Measure Volume: Ruler, Graduated Cylinder, Beaker

Mass Mass-is the amount of matter that an object contains SI Unit for Mass is measured in kilograms (kg) Grams (g) are also used but are very small

Time Time- is the interval between two events Unit of time is the second

Temperature Temperature- is the measure of the average kinetic energy of particles Temperature is measured in Kelvin (K) in the SI system K = 273 + °C ˚C= K- 273 Temperature is usually given in °C

Convert the following temperatures 1. 36 °C to K 2. 50 K to °C 3. 105 K to °C 4. -236 °C to K

Terms Used for Measurements In comparing scientific results, the following terms are applied: a. accuracy b. precision

The closer the value is to the true value, the more accurate one is Accuracy Accuracy refers to the agreement of one experimental result to the true or accepted value The closer the value is to the true value, the more accurate one is

hitting a three point shot determining the value of  to be 3.13 Accuracy Examples of accuracy: kicking a soccer goal hitting a three point shot determining the value of  to be 3.13

Practice: Tell if the accuracy is good or poor a. Finding the percent H2O2 to be 2.9% (the bottle says it contains 3%) b. Finding that a 2 Liter bottle only contains 1.5 Liters of soda c. Filling a 1000 mL volumetric flask with 1050 mL of water

Precision Precision refers to how close several different experimental values are to each other

Precision Examples: scoring three goals in a soccer game Shooting an air ball five times finding the value for  to be 3.12, 3.15, 3.13

Precision and Accuracy Problems Precision problems usually arise from the skill of the person doing the experiment or the division of the measuring instruments Accuracy problems usually related to the quality of the equipment used to make measurements

Precision and Accuracy

Describe the accuracy and precision of the following as either good or poor A student makes the following grades: a. 99, 100, 98, 100 b. 45, 43, 44, 42 c. 100, 23, 60, 89

Hazmat Diamond