METRIC SYSTEM THE INTERNATIONAL SYSTEM OF MEASUREMENT USED BY SCIENTISTS (SI SYSTEM) THE INTERNATIONAL SYSTEM OF MEASUREMENT USED BY SCIENTISTS (SI SYSTEM)

Making Scientific Measurements When scientists make observations and measurements, it is not sufficient to say that something is “big” or “heavy”, “long” or “short.” Qualitative Measurements are general terms and are not specific enough for science. Examples include: Big, heavy, and warm. Quantitative Measurements are specific and are the type of measurements scientists use. Examples include: 500cm 3, 70g, and 100°C. Quantity = #

UNITS OF MEASURE METRIC SYSTEM LENGTH METERS MASS GRAMS VOLUME LITERS TEMPERATURE CELCIUS DENSITY GRAMS CC OR ML

Making Scientific Measurements Scientists use a standard system of measurement know as the: International System of Units (SI system). Each unit is 10 times larger than the next smallest unit. Common SI prefixesSymbolMeaning Kilo- k1,000 Hecto- h100 Deka- da10 Deci- d0.1 one tenth Centi- c0.01 one hundredth Milli- m0.001 one thousandth SYSTEM IS BASED ON THE NUMBER SYSTEM IS BASED ON THE NUMBER

Length (distance) Length is the: distance between two points. FACTS ABOUT LENGTH MEASURMENTS: The unit for distance is the meter (m). Small distances measured in centimeters (cm) or millimeters (mm) Large distances (here to Richmond) measured in kilometers (km) 1 km= 1000 m 1 m = 100 cm 1 m= 1,000 mm 1 cm= 10 mm Common Conversions

Temperature Temperature is the: average motion of molecules in a substance. Hot = faster motion Cold = slower motion FACTS ABOUT TEMPERATURE MEASURMENTS: The unit for temperature is a degree. Scientists use the Celsius Scale °C to measure temperature. Water boils at 100°C and freezes at 0°C 0 C TO 0 F (C X 1.8) F TO 0 C (F – 32) / 1.8 Thermometer

Area Area is the: size of a region or space. FACTS ABOUT AREA MEASURMENTS: Area is found by multiplying two distances. Area = (Length) x (Width) Units are also multiplied and become “squared” 2 20 m Length = 20m Width = 20m (20m) X (20m) = 400m 2

Volume (square objects, like a box) Volume is the: amount of space something takes up. FACTS ABOUT VOLUME MEASURMENTS: Volume is found by multiplying three distances. Volume = (Length) x (Width) x (Height) Units are also multiplied and become “cubed” 3 20 m 10 m Length = 10m Width = 10m Height = 20m (10m) X (10m) X (20m) = 2000m 3

Volume (liquid, like water in a cup) FACTS ABOUT LIQUID VOLUME MEASURMENTS: The unit for liquid volume is the Liter (L). Volume is found using a graduated cylinder. Units for small volumes are milliliters (ml). You should always read a graduated cylinder at the bottom of the curve of the liquid. That curve is called the meniscus L= 1000 mL Common Conversions Volume of irregular shaped objects use water displacement

MASS (G) Mass is the: amount of matter “stuff” something is made of. Mass will not change unless you add or take away matter. FACTS ABOUT MASS MEASURMENTS: The unit for mass is the gram (g). Large masses are measured in kilograms (kg). A triple beam balance (NOT A SCALE) is used to measure mass. 1 kg= 1000 gCommon Conversions

Weight Weight is: how much gravity pulls on you or on any other object, such as a planet. Gravity changes from one place to another and thus so does your weight. The more massive the object, the more it will pull on you... AND THE HIGHER YOUR WEIGHT WILL BE. 150 Newtons 25 Newtons You press down less on the scale. MOON 1/6 the gravity

Density Density is: how closely packed particles in a substance are. Said another way, Density is: the amount of matter (mass) in a given space (volume). Density = mass (g) volume (cm 3 ) m= 10g m = 10g v = 10cm 3 v = 2cm 3 d= 1g/cm 3 d= 5g/cm 3 LESS DENSE MORE DENSE

Density Density = mass (g) volume (cm 3 ) FACTS ABOUT DENSITY MEASURMENTS: Density is found by dividing a mass (g) or (kg) and a volume (cm 3 ) or (ml). Units must also be divided: Example: g/cm 3. Mass = 20g Volume = 10cm 3

Density Density = mass (g) volume (cm 3 ) Given any two of these quantities (density, mass, or volume) you can find the other by either multiplying or dividing appropriately. Density = 2g Volume = 10cm 3 Mass = ? (2g) x (10cm 3 ) m d v