Bell Work: Units (I’ll collect labs after the bell assignment) Arrange the prefixes from largest to smallest quantity: milli-, kilo-, Mega-, nano-, base, centi- Arrange the units from smallest to largest. meter, inch, mile, kilometer, second, foot, centimeter Which quantity in question 2 shouldn’t be there? Answer: Mega-, kilo-, base, centi-, -milli-, nano- 2. Answer: centimeter, inch, foot, meter, km, mile FYI: there are 1.6 km in 1 mile.

Collecting Labs Place your lab on your desk number Does your heading include first and last name? Date? Period? Is your neighbor absent? If you don’t have a lab to turn in, fill out a yellow NTI (Not Turned In) form to turn in instead.

Safety Contracts Required to complete labs Print your name on the front Answer questions 56-58 Sign the back Get the back signed by a parent tonight! Bring back to class tomorrow!

Units are of Utmost Importance Would you rather have 10 cents or 10 dollars? Would you rather run 10 meters or 10 kilometers? Would you rather stay out 3 minutes or 3 hours late? Would you rather have a pound or kilogram of (fill in your favorite food) ?

SI UNITS The worldwide scientific community and most countries currently use an adaptation of the metric system to state measurements. The Système International d’Unités, or SI, uses 7 base quantities, which are below.

DERIVED UNITS Defined by a combination of base units Speed: Acceleration: Force: 𝑚/𝑠 𝑚/ 𝑠 2 Newton=𝑘𝑔∙ 𝑚/𝑠 2

PREFIXES USED WITH SI UNITS King Henry Died By Drinking Chocolate Milk K H D B D C M Kilo 1000 units Hecto 100 units Deka 10 units Base Unit Deci 0.1 units Centi 0.01 units Milli 0.001 units

PREFIXES USED WITH SI UNITS Kilo 1000 units Hecto 100 Deka 10 Basic Unit Deci 0.1 Centi 0.01 Milli 0.001

Prefixes used with SI Units

MOVE THE DECIMAL To convert from base to kilo, move the decimal _____ places to the ( right / left ). To convert from centi to base, move the decimal _____ places to the ( right / left ). To convert from millimeters to centimeters, move the decimal _____ places to the ( right / left ). To convert from kilograms to grams, move the decimal _____ places to the ( right / left ). 3 2 1 3

End PRACTICE 5 Minute Timer Get as many done as you can in 5 minutes. www.A6training.co.uk

Check your answers. . . . 0.261 kg 2 cm 0.00073 L 0.075 kg 4650 m 0.042658 km 5600 g 49,000 cm 0.0002 m

Dimensional Analysis (AKA Factor Label) Dimensional analysis uses a conversion factor to convert from one unit to another. A conversion factor is a multiplier equal to 1. For example, because 1 minute = 60 seconds, you can construct the following conversion factors: 𝑥 1 𝑚𝑖𝑛𝑢𝑡𝑒 60 𝑠𝑒𝑐𝑜𝑛𝑑𝑠 𝑎𝑛𝑑 𝑥 60 𝑠 1 𝑚𝑖𝑛

900 1 𝑚𝑖𝑛 60 𝑠 Should you multiply or divide?? The starting (given) unit goes on the bottom of the factor. The unit you are looking for goes on the top of the factor. 𝑥 𝑙𝑜𝑜𝑘𝑖𝑛𝑔 𝑓𝑜𝑟 𝑠𝑡𝑎𝑟𝑡𝑖𝑛𝑔 𝑤𝑖𝑡ℎ Example: How many seconds are in 15 minutes? 15 minutes 𝑥 = ________ seconds 1 𝑚𝑖𝑛 60 𝑠 900 Should you multiply or divide??

Practice Together 5400 16.4 78 27,720 10,680 60 𝑠 1 𝑚𝑖𝑛 1 𝑚𝑖𝑛 60 𝑠 90 minutes 𝑥 = ________ seconds 985 s 𝑥 = ________ min 1. 3 h 𝑥 = ________min 7.7 h 𝑥 = _____________ s 178 min 𝑥 = ___________ s 5400 1 𝑚𝑖𝑛 60 𝑠 16.4 60 𝑚𝑖𝑛 1 ℎ 78 3600 𝑠 1 ℎ 27,720 60 𝑠 1 𝑚𝑖𝑛 10,680

End PRACTICE 10 Minute Timer Get as many done as you can in 10 minutes. 10 Minute Timer End www.A6training.co.uk

Significant Figures (Digits) and Measuring The numbers in measurements are limited by the measuring tool. Significant figures in a measurement include the known digits plus one estimated digit.

Practice more measuring

1. What is the 1st measurement? 1.42 cm OR 1.43 cm OR 1.44 cm 2. What is the 2nd measurement? 2.7cm OR 2.6 cm

How long are the pencils?

Activity Measure the length of 5 objects in centimeters with as much precision as possible (estimate the last digit). Convert all lengths to meters. Create a data table including the object name, length in cm, and length in m If finished, turn in before you leave to the early basket!

Ticket out the door.