Unit Conversions By Tim Fahlberg Please feel free to me!

Objectives Convert units within the metric system. Convert units within the metric system. Convert units between the metric and apothecary system. Convert units between the metric and apothecary system. A-2

How confident do you feel about using the metric system? A. Very confident B. Somewhat confident C. Not very confident D. What’s the metric system?

How confident do you feel about your math skills (i.e. algebra)? A. Very confident B. Somewhat confident C. Not very confident D. I have no confidence about being able to do math

Do you enjoy math? A. Yes, math is great! B. Yeah, I like math pretty well C. I’m ambivalent about math D. I don’t like math E. I hate math

The metric system Quick check/test: Quick check/test:

The metric system is a decimal system based on Multiples of 10 Fractions of 10 A-2

What are the basic units of measurement in the metric system? Grams Liters Meters A-3

What do these units measure? Grams   Unit for weight Liters   Unit for volume or capacity Meters   Unit for length A-6

What are 4 different ways to write grams? g gm gm G Gm Gm A-4

What are 2 different ways to write liters? l L A-2

What are 2 different ways to write meters? m M A-2

Metric prefixes commonly used in medicine Larger units Larger units  kilo (k) - kg Smaller units Smaller units  centi (c) – cm (think hundredth – like cents in a dollar)  milli (m) – mm, ml, mg (think thousandth)  micro (mc) – mcg (think millionth)

Weight per gram 1 kilogram (kg) = ____ g 1 kilogram (kg) = ____ g  gram (g) = 1 g 1 gram (g) = 1 g 1 milligram (mg) = ____ g 1 milligram (mg) = ____ g .001 (again – think thousandth) 1 microgram (mcg) = ____ g 1 microgram (mcg) = ____ g  (again – think millionth)

Volume per liter 1 liter (l) = 1 liter 1 liter (l) = 1 liter 1 milliliter (ml) = ___ liter 1 milliliter (ml) = ___ liter .001

Length per meter 1 kilometer (km) = _____ meters 1 kilometer (km) = _____ meters  meter (m) = 1 meter 1 meter (m) = 1 meter 1 centimeter (cm) = ____ meter 1 centimeter (cm) = ____ meter .01 1 millimeter (mm) = ____ meter 1 millimeter (mm) = ____ meter .001

Metric units review (Length) 1 m = ____ cm 1 m = ____ cm  1 m = 100 cm 1 cm = ____ m 1 cm = ____ m  1 cm =.01 m

Metric units review (Length) 1 m = ____ mm 1 m = ____ mm  1 m = 1000 mm 1 mm = ____ m 1 mm = ____ m  1mm =.01 m

Metric units review (Weight) 1 kg = ____ g 1 kg = ____ g  1 kg = 1000 g 1 g = ____ kg 1 g = ____ kg  1 g =.001 kg

Metric units review (Weight) 1 g = ____ mg 1 g = ____ mg  1 g = 1000 mg 1 mg = ____ g 1 mg = ____ g  1 mg =.001 g

Metric units review (Weight) 1 g = ____ mcg 1 g = ____ mcg  1 g = 1,000,000 mg 1 mcg = ____ g 1 mcg = ____ g  1 mcg = g

Metric units review (Volume) 1 l = ____ ml 1 l = ____ ml  1 l = 1,000 ml 1 ml = ____ l 1 ml = ____ l  1 ml =.001 l

Conversion within the Metric System Why is this important? Why is this important?  Drug administration often requires conversion within the metric system to prepare the correct dosage.

Conversion within the Metric System Two methods: Two methods:  Changing from a larger unit to a smaller unit.  For example, “Change 1 g to mg.”  Changing from a smaller unit to a larger unit.  For example, “Change 120 ml to l.”

Conversion within the Metric System To change from a larger unit to a smaller unit: To change from a larger unit to a smaller unit:  Multiply by the correct power of 10 or use the conversion factor.

Problem 1: Convert 2.5 liters (l) to milliliters (ml) Convert 2.5 liters (l) to milliliters (ml)  Ask: “Which is bigger, 1 L or 1 ml?”   So, are there a bunch of liters in a ml or a bunch of ml in a liter? And how many?  Should the answer be more or less than 2.5?  Let’s do the calculation … (Next slide please)

Problem 1: (Continued) Convert 2.5 liters (L) to milliliters (mL) Convert 2.5 liters (L) to milliliters (mL)  Ask: “Is this answer reasonable?”

Problem 2: Convert 4.8 grams (g) to milligrams (mg) Convert 4.8 grams (g) to milligrams (mg)  Ask: “Which is bigger, g or mg?”   So, are there a bunch of grams in a mg or mg in a gram? How many?   Should the answer be more or less than 4.8?   Let’s do the calculation … (Next slide please)

Problem 2: (Continued) Convert 4.8 grams (g) to milligrams (mg) Convert 4.8 grams (g) to milligrams (mg)  Ask: “Is this answer reasonable?”

Conversion within the Metric System To change from a smaller unit to a larger unit: To change from a smaller unit to a larger unit:  Divide by powers of 10 or use the conversion factor.

Problem 3: Convert 1300 milliliters (ml) to liters(l) Convert 1300 milliliters (ml) to liters(l)  Ask: “Which is bigger, ml or l?”   So, are there a bunch of milliliters in a liter or liters in a milliliter? How many?   Should the answer be more or less than 1300?   Let’s do the calculation … (Next slide please)

Problem 3: (Continued) Convert 1300 milliliters (ml) to liters(l) Convert 1300 milliliters (ml) to liters(l)  Ask: “Is this answer reasonable?”

Problem 4: A patient problem A patient problem  Joe weighs in at the health clinic and notices that he’s gained 5 kg of weight since yesterday.  How much fluid might he have gained since yesterday?

Problem 5: The doctor has prescribed 0.15 mg of a drug. The doctor has prescribed 0.15 mg of a drug. How many micrograms is this? How many micrograms is this?  Ask: “Which is bigger, milligrams (mg) or micrograms (mcg)?”  So, are there a bunch of milligrams in a microgram or vice versa? How many?   Should the answer be more or less than 0.15?  Let’s do the calculation … (Next slide please)

Problem 5: (Continued) Convert 0.15 mg to mcg. Convert 0.15 mg to mcg.  Ask: “Is this answer reasonable?”

Problem 6: A wound on a patient is 7.5 mm. A wound on a patient is 7.5 mm. How many cm is this? How many cm is this?  Ask: “Which is bigger, mm or cm?”  So, are there a bunch of mms in a cm or vice versa? How many?   Should the answer be more or less than 7.5?   Let’s do the calculation … (Next slide please)

Problem 6: (Continued) Change 7.5 mm to cm. Change 7.5 mm to cm.  Ask: “Is this answer reasonable?”

The Apothecary System What are the basic units of measurement in the apothecary system that are most useful in nursing? What are the basic units of measurement in the apothecary system that are most useful in nursing?  Weight   Grains (gr)   Liquid volume   Quarts (qt)   Pints (pt)   Fluid ounces (fl oz)

The Household System What are the basic units of measurement in the household system that are most useful in nursing? What are the basic units of measurement in the household system that are most useful in nursing?  Teaspoons (tsp)  Tablespoons (Tbsp)  Ounces (oz)  Cups

Conversion - Apothecary– Metric – Household Systems How many … ? How many … ?Weight   ___ milligram(s) (mg) = ___ grain(s) (gr)?   Approximately 60 mg = 1 gr

Conversion - Apothecary– Metric - Household Systems How many … ? How many … ? Volume   ___ pint(s) = ___ quart(s) (qt)   2 pt = 1 qt   ___ fluid ounce(s) (oz) = ___ cc   1 fl oz = 30 cc

Conversion - Apothecary– Metric – Household Systems How many … ? How many … ? Volume (Continued)   ___ Tablespoons = ___ Fl oz = ___ cc   2 Tbsp = 1 fl oz = 30 cc   ___Tbsp = ___ cc   1 Tbsp = 15 cc

Conversion - Apothecary– Metric – Household Systems How many … ? How many … ? Volume (Continued)   ___ Teaspoons = ___ Tablespoons = ___ cc   3 tsp = 1 Tbsp = 15 cc   ___ tsp = ___ cc   1 tsp = 5 cc  ___ cup = ___ oz = ___ cc  1 c = 8 oz = 240 cc