Chapter 1 Lesson 3 (cont.) “How to Use the S.I. System”

Introduction mg Prefix Unit measured milli gram

I. Length A. Def – the distance between 2 points 1. base unit = meter 2. Examples a. meter, millimeter, hectometer

Length Example Convert: a meters  cm = cm b km  mm = 3400 mm c dm  decameters = decameters

II. Volume (derived unit) A. Def. – the amount of space occupied 1. formula: length X width X height 2. base unit = liter (liquids); meter (solids) a. **1 cm 3 = 1 ml** 3. solids are always cubed (cm 3, m 3 ) 4. for liquids, use container dimensions to calculate volume 5. is a derived unit which means it is obtained by combining SI units

Volume Example A liquid is poured into a container. If the dimensions of the container are 45 ml, 54 ml, and 80 ml what is the volume of the liquid in ml 3 ?  194,400 cm 3 The sides of a box are 45 cm, 54 cm, and 0.4 dm. What is the volume of the box in cm 3 ?  9,720 cm 3

III. Mass A. Def. – the amount of matter in an object 1. base unit = gram 2. kilograms is used frequently 3. ex: golf ball vs. table tennis ball

Mass Example Convert: a. 54 g  kg.054 kg b kg  mg 3,002,000 mg

IV. Density (derived unit) A. Def. – Mass per unit of volume 1. formula: density = mass / volume 2. derived unit of mass and volume

Density Example What is the density of an unknown metal that has a mass of grams and a volume of 20.0 mL? ***Remember D=M/V***  8.9 grams/mL Will this object float in water??? (1.0 g/ml)

V. Time and Temperature A. Def. – Time is the interval between two events. 1. Base unit = second B. Def. – Temperature is the amount of heat contained in a substance 1. Base unit = Kelvin/Celsius

Temperature Scales a. Celsius Scale – used for most scientific work i. 0 = freezing point of water ii. 100 = boiling point of water iii. 20 = room temperature iv. 37 = body temperature b. Kelvin scale i. 0 on the Kelvin Scale is absolute zero (-273 C.) ii. to convert Celsius to Kelvin add 273 K iii. to convert Kelvin to Celsius subtract 273 K

Temperature Example The outside temperature is 29 degrees Celsius. What is it in Kelvin?  302 Kelvin A person has a temperature of 313 Kelvin. Does this person have a fever?  yes; the body temp is 40 deg C.