The Methods of Science Standards of Measurement To have accurate measurements, you must have a standard, which is an exact quantity that people agree to use for comparison The system of measurements that is universally accepted and understood by scientists is the International System of Units (SI)

The Methods of Science SI Base Units Quantity Measured Unit Symbol Length Mass Time Electric Current Temperature Amount of Substance Intensity of LIght

The Methods of Science SI Base Units Quantity Measured Unit Symbol Length meter m Mass Time Electric Current Temperature Amount of Substance Intensity of LIght

The Methods of Science SI Base Units Quantity Measured Unit Symbol Length meter m Mass gram g Time Electric Current Temperature Amount of Substance Intensity of LIght

The Methods of Science SI Base Units Quantity Measured Unit Symbol Length meter m Mass gram g Time second s Electric Current Temperature Amount of Substance Intensity of LIght

The Methods of Science SI Base Units Quantity Measured Unit Symbol Length meter m Mass gram g Time second s Electric Current ampere A Temperature Amount of Substance Intensity of LIght

The Methods of Science SI Base Units Quantity Measured Unit Symbol Length meter m Mass gram g Time second s Electric Current ampere A Temperature kelvin K Amount of Substance Intensity of LIght

The Methods of Science SI Base Units Quantity Measured Unit Symbol Length meter m Mass gram g Time second s Electric Current ampere A Temperature kelvin K Amount of Substance mole mol Intensity of LIght

The Methods of Science SI Base Units Quantity Measured Unit Symbol Length meter m Mass gram g Time second s Electric Current ampere A Temperature kelvin K Amount of Substance mole mol Intensity of LIght candela cd

The Methods of Science Measuring Time time – the interval between two events the SI unit for time is the second

The Methods of Science Measuring Temperature temperature – a measure of how hot or cold something is the SI unit for temperature is the kelvin to change Celsius to Kelvin, K = C + 273 to change Kelvin to Celsius, C = K – 273

The Methods of Science Temperature

The Methods of Science Measuring Distance – also referred to as measuring length the units used to measure length depend on what is being measured example: meters may be used to measure the length of a field example: micrometers may be used to measure the length of a bacteria

volume = length x width x height The Methods of Science Measuring Volume volume – the amount of space that an object occupies solids - to measure the volume of a solid object, you multiply the length, width, and height units for volumes of solids will almost always be cubed (ex. m3, cm3, and mm3) volume = length x width x height

The Methods of Science volume – the amount of space that an object occupies liquids - to measure the volume of a liquid, you measure the capacity of the container that holds the liquid the units for measuring volumes of liquids will usually be in liters or milliliters changing from volumes of solids to volumes of liquid 1 L = 1dm3 & 1 mL = 1 cm3

The Methods of Science Measuring Matter mass – a measurement of the quantity of matter in an object mass is usually measured in grams (g) or kilograms (kg)

The Methods of Science Measuring Matter density – the mass per unit volume of a material density can be thought of as how “compact” something is you find density by taking the mass of an object and dividing by its volume

The Methods of Science density – the mass per unit volume of a material Example: What is the density of a metal that has a mass of 158g and a volume of 20 ml? 158g D = =7.9 g/ml 20 ml

The Methods of Science 1) mass= 9.9g; Volume= 25 mL; Density =? 2) mass=?; Volume= 30mL; Density= 80 g/mL 3) mass= 45g; Volume=?; Density= 8.00 g/mL

The Methods of Science The SI system is easy to use because it uses SI prefixes which is based on multiples of 10 example: milli means one-thousandth (0.001 meters)

The Methods of Science Kilo- Hecta- Deca- Base unit Deci- Centi- Common SI Prefixes Prefix Symbol Multiplying Factor Kilo- Hecta- Deca- Base unit Deci- Centi- Milli-

The Methods of Science Kilo- k 1,000 Hecto- Deca- Base unit Deci- Common SI Prefixes Prefix Symbol Multiplying Factor Kilo- k 1,000 Hecto- Deca- Base unit Deci- Centi- Milli-

The Methods of Science Kilo- k 1,000 Hecto- h 100 Deca- Base unit Common SI Prefixes Prefix Symbol Multiplying Factor Kilo- k 1,000 Hecto- h 100 Deca- Base unit Deci- Centi- Milli-

The Methods of Science Kilo- k 1,000 Hecto- h 100 Deca- da 10 Common SI Prefixes Prefix Symbol Multiplying Factor Kilo- k 1,000 Hecto- h 100 Deca- da 10 Base unit Deci- Centi- Milli-

The Methods of Science Kilo- k 1,000 Hecto- h 100 Deca- da 10 Common SI Prefixes Prefix Symbol Multiplying Factor Kilo- k 1,000 Hecto- h 100 Deca- da 10 Base unit 1 Deci- Centi- Milli-

The Methods of Science Kilo- k 1,000 Hecto- h 100 Deca- da 10 Common SI Prefixes Prefix Symbol Multiplying Factor Kilo- k 1,000 Hecto- h 100 Deca- da 10 Base unit 1 Deci- d 0.1 Centi- Milli-

The Methods of Science Kilo- k 1,000 Hecto- h 100 Deca- da 10 Common SI Prefixes Prefix Symbol Multiplying Factor Kilo- k 1,000 Hecto- h 100 Deca- da 10 Base unit 1 Deci- d 0.1 Centi- c 0.01 Milli-

The Methods of Science Kilo- k 1,000 Hecto- h 100 Deca- da 10 Common SI Prefixes Prefix Symbol Multiplying Factor Kilo- k 1,000 Hecto- h 100 Deca- da 10 Base unit 1 Deci- d 0.1 Centi- c 0.01 Milli- m 0.001

The Methods of Science Metric to Metric Unit Conversions Units Sometimes quantities need to be converted from one unit to another. How do we do that? Example: You have a length of rope that measures .7 dam. How long is that rope in dm? Example: You live 50000000 mm away from school. How many km is this?

The Methods of Science Kilo (k) 1000x Hector (h) 100x Deka (da) 10x Centi (c) 1/100 Milli (m) 1/1000 Deci (d) 1/10 BASIC UNIT King Henry Doesn’t Usually Drink Chocolate Milk To convert to a smaller unit, move decimal point to the right To convert to a larger unit, move decimal point to the left

The Methods of Science Converting Between English and Metric Units Sometimes quantities are measured using different units and conversion factors are used to change from one unit to another. To properly convert units there are 5 rules that need to be followed when converting between the English and Metric system.

The Methods of Science Rules for Converting Between Units 1. Identify your “given” and “find” the information given to you in the problem and the units you need to convert these to 2. Put the “given” in the top left corner of your railroad tracks The units on the top and bottom of the railroad track need to be the same so that your units cancel out. 4. Use order of operations to solve for your final answer 5. Double check that you cancelled out all units correctly. Given

The Methods of Science Converting Between Si Units Sometimes quantities are measured using different units and conversion factors are used to change from one unit to another. Example: You have a length of rope that measures 3,075 mm. How long is it in feet (ft)?

The Methods of Science Converting Between Si Units Example: You have a length of rope that measures 3,075 mm. How long is it in feet (ft)? Given: 3,075 mm Find: ? ft .00328 ft 3,075 mm = 10.09 ft 1 mm

The Methods of Science Converting Between Si Units Example: You travel a distance of 5.5 km. How far did you travel in miles (mi)?

The Methods of Science Converting Between Units Example: You are counting down the days until spring break, which is 21 days away. How many seconds away is this?

The Methods of Science Uncertainty in Measurements Accuracy The closeness of a measurement to the actual value of what is being measured. Example: In throwing darts, you aim at the bulls eye and hit the bulls eye Example: You measure the mass of an object three times and obtain values of 35g, 36g, and 35g when the actual mass is 34.5g.

The Methods of Science Uncertainty in Measurements Precision The reproducibility of a set of measurements taken under the same conditions. This describes how closely grouped your data points are. Example: In throwing darts, all three darts hit the 20. Example: You measure the mass of an object three times and obtain values of 35g, 36g, and 35g when the actual mass is 48.5g.

The Methods of Science