Warmup 9/21/15 How many millimeters are in a kilometer? What other conversions between units do you know? Objective Tonight’s Homework To refresh on how to convert metric units Finish conversion worksheet

The Metric System Today we’re going to start discussing chemistry. We’re going to begin with units. In chemistry, we often need be careful with measurement because we’re often dealing with very precise things. So to start, let’s take notes of the different metric prefixes and how big or small each one means.

Notes on Metric Conversion We attach prefixes – a group of letters – in front of each metric unit to tell us how much bigger or smaller we want it. prefixlettersize - megaM 1,000, kilok 1,000 - hectoh dekada10 - “normal”-1 - decid0.1 - centic millim microμ

Notes on Metric Conversion To convert units, we have a simple trick. - If we’re converting to something bigger, we move the decimal to the left. (Divide) - If we’re converting to something smaller, we move the decimal to the right. (Multiply) The letter after each prefix tells us what we’re measuring. m = metersL = litersg = grams Example: Convert 28 mm to km. We want to go up the table, so we need to move our decimal left. We’re going up 6 steps, so we move our decimal left mm  km

Practice with Metric Conversion cl = ____ L mm = ____ cm cl = ____ L 4. 2 cm = ____ mm L = ____ kL6. 10 cl = ____mL m = ____ km 8. 8 g = ____ cg9. 80 ml = ____ cL L = ____ cL L = ____ kL12. 5 cm = ___ mm cm = ____ m cg = ____ μg m = __ km ml = ____ L kg = ____ g mm = __ cm kg = ____ g ml = ____ L21. 1 cl = ____ mL L = ____hL g = __ Mg μl = __ L L = ____ kL ml = ____ cL27. 5 g = ____ cg cl = ____ mL g = ____ cg30. 8 kg = ____ g

Exit Question How many dekameters are in a hectometer? a) 1 b) 10 c) 100 d) 1000 e) 0.1 f) None of the above