Unit Conversions

Unit Conversions

ByBy

Tim FahlbergTim Fahlberg

[email protected]@gmail.com

Please feel free to email me!Please feel free to email me!

Objectives

Convert units within the metric system.Convert units within the metric system. Convert units between the metric and Convert units between the metric and

apothecary system.apothecary system.

A-2

How confident do you feel about using the metric system?

A.A. Very confidentVery confidentB.B. Somewhat confidentSomewhat confidentC.C. Not very confidentNot very confidentD.D. What’s the metric system?What’s the metric system?

How confident do you feel about your math skills (i.e. algebra)?

A.A. Very confidentVery confidentB.B. Somewhat confidentSomewhat confidentC.C. Not very confidentNot very confidentD.D. I have no confidence about being able to I have no confidence about being able to

do mathdo math

Do you enjoy math?

A.A. Yes, math is great!Yes, math is great!B.B. Yeah, I like math pretty wellYeah, I like math pretty wellC.C. I’m ambivalent about mathI’m ambivalent about mathD.D. I don’t like mathI don’t like mathE.E. I hate mathI 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?

gg gmgm GG GmGm

A-4

What are 2 different ways to write liters?

ll LL

A-2

What are 2 different ways to write meters?

mm MM

A-2

Metric prefixes commonly used in medicine

Larger unitsLarger units kilo (k) - kgkilo (k) - kg

Smaller unitsSmaller units centi (c) – cm (think hundredth – like centi (c) – cm (think hundredth – like

cents in a dollar)cents in a dollar) milli (m) – mm, ml, mg (think milli (m) – mm, ml, mg (think

thousandth)thousandth) micro (mc) – mcg (think millionth)micro (mc) – mcg (think millionth)

Weight per gram 1 1 kilokilogram (kg) = ____ ggram (kg) = ____ g

10001000 1 gram (g) = 1 g1 gram (g) = 1 g 1 1 millimilligram (mg) = ____ ggram (mg) = ____ g

.001 (again – think thousandth).001 (again – think thousandth) 1 1 micromicrogram (mcg) = ____ ggram (mcg) = ____ g

.000001 (again – think millionth).000001 (again – think millionth)

Volume per liter

1 liter (l) = 1 liter1 liter (l) = 1 liter 1 1 millimilliliter (ml) = ___ literliter (ml) = ___ liter

.001.001

Length per meter

1 1 kilokilometer (km) = _____ metersmeter (km) = _____ meters 10001000

1 meter (m) = 1 meter1 meter (m) = 1 meter 1 1 centicentimeter (cm) = ____ metermeter (cm) = ____ meter

.01.01 1 1 millimillimeter (mm) = ____ metermeter (mm) = ____ meter

.001 .001

Metric units review (Length) 1 m = ____ cm1 m = ____ cm

1 m = 100 cm1 m = 100 cm

1 cm = ____ m1 cm = ____ m 1 cm = .01 m1 cm = .01 m

Metric units review (Length) 1 m = ____ mm1 m = ____ mm

1 m = 1000 mm1 m = 1000 mm

1 mm = ____ m1 mm = ____ m 1mm = .01 m1mm = .01 m

Metric units review (Weight) 1 kg = ____ g1 kg = ____ g

1 kg = 1000 g1 kg = 1000 g

1 g = ____ kg1 g = ____ kg 1 g = .001 kg1 g = .001 kg

Metric units review (Weight) 1 g = ____ mg1 g = ____ mg

1 g = 1000 mg1 g = 1000 mg

1 mg = ____ g1 mg = ____ g 1 mg = .001 g1 mg = .001 g

Metric units review (Weight) 1 g = ____ mcg1 g = ____ mcg

1 g = 1,000,000 mg1 g = 1,000,000 mg

1 mcg = ____ g1 mcg = ____ g 1 mcg = .000001 g1 mcg = .000001 g

Metric units review (Volume) 1 l = ____ ml1 l = ____ ml

1 l = 1,000 ml1 l = 1,000 ml

1 ml = ____ l1 ml = ____ l 1 ml = .001 l1 ml = .001 l

Conversion within the Metric System

Why is this important?Why is this important?

Drug administration often requires Drug administration often requires conversion within the metric system conversion within the metric system to prepare the correct dosage.to prepare the correct dosage.

Conversion within the Metric System

Two methods:Two methods:

ChangingChanging from a larger unit to a smaller unit. from a larger unit to a smaller unit. For example, “Change 1 g to mg.”For example, “Change 1 g to mg.”

Changing from a smaller unit to a larger unit.Changing from a smaller unit to a larger unit. For example, “Change 120 ml to l.”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 Multiply by the correct power of 10 or use the conversion factor.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?”Ask: “Which is bigger, 1 L or 1 ml?”

So, are there a bunch of liters in a ml or a bunch So, are there a bunch of liters in a ml or a bunch of ml in a liter? And how many?of ml in a liter? And how many?

Should the answer be more or less than 2.5?Should the answer be more or less than 2.5?

Let’s do the calculation … (Next slide please)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?”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?”Ask: “Which is bigger, g or mg?”

So, are there a bunch of grams in a mg or mg in So, are there a bunch of grams in a mg or mg in a gram? How many?a gram? How many?

Should the answer be more or less than 4.8?Should the answer be more or less than 4.8?

Let’s do the calculation … (Next slide please)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?”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 Divide by powers of 10 or use the

conversion factor.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?”Ask: “Which is bigger, ml or l?”

So, are there a bunch of milliliters in a liter or So, are there a bunch of milliliters in a liter or liters in a milliliter? How many?liters in a milliliter? How many?

Should the answer be more or less than 1300?Should the answer be more or less than 1300?

Let’s do the calculation … (Next slide please)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?”Ask: “Is this answer reasonable?”

Problem 4: A patient problem A patient problem

Joe weighs in at the health clinic and Joe weighs in at the health clinic and notices that he’s gained 5 kg of weight notices that he’s gained 5 kg of weight since yesterday. since yesterday. How much fluid might he have gained How much fluid might he have gained

since yesterday? 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 Ask: “Which is bigger, milligrams (mg) or micrograms (mcg)?”micrograms (mcg)?”

So, are there a bunch of milligrams in a So, are there a bunch of milligrams in a microgram or vice versa? How many?microgram or vice versa? How many?

Should the answer be more or less than 0.15?Should the answer be more or less than 0.15?

Let’s do the calculation … (Next slide please)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?”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?”Ask: “Which is bigger, mm or cm?”

So, are there a bunch of mms in a cm or vice So, are there a bunch of mms in a cm or vice versa? How many?versa? How many?

Should the answer be more or less than 7.5?Should the answer be more or less than 7.5?

Let’s do the calculation … (Next slide please)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?”Ask: “Is this answer reasonable?”

The Apothecary System

What are the basic units of measurement in the What are the basic units of measurement in the apothecary system that are most useful in nursing?apothecary system that are most useful in nursing?

WeightWeight Grains (gr)

Liquid volume Quarts (qt) Pints (pt) Fluid ounces (fl oz)

The Household System

What are the basic units of measurement in What are the basic units of measurement in the household system that are most useful in the household system that are most useful in nursing?nursing?

Teaspoons (tsp)Teaspoons (tsp) Tablespoons (Tbsp)Tablespoons (Tbsp) Ounces (oz)Ounces (oz) CupsCups

Conversion - Apothecary– Metric – Household Systems

How many … ?How many … ?

WeightWeight ___ 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___ cup = ___ oz = ___ cc 1 c = 8 oz = 240 cc1 c = 8 oz = 240 cc