3c- Units

REDUCING BIAS WITH NUMERICAL MEASUREMENTS

A good science project uses units. State what units you will record your numerical measurements in.

example: I will record the measurements in the following units: centimeters

Examples of some commonly used numerical (quantitative) measurements include:

MEASUREMENT	EXAMPLES	DEVICE OR EQUIPMENT USED	UNITS
LENGTH how long something is	height of a plant distance football kicked	ruler tape measure	millimeters (mm) centimeters (cm) meters (m)
VOLUME how much space something takes up	amount of water absorbed amount of juice squeezed	graduated cylinder measuring cup	milliliters (mL) liters (L)
MASS how much matter something is made of	how heavy a nail is how heavy a worm is	triple beam balance spring scale bathroom scale	milligrams grams kilograms
TEMPERATURE how hot or cold something is	temperature of air temperature of object	thermometer	degrees Celsius
TIME how long it takes to do something	time to run 100 meters time to dry	clock watch stop watch	seconds minutes hours

If an actual numerical measurement is not obtainable, descriptive observations can be quantified by creating a numerical scale. A numerical scale assigns numbers to a range of descriptive outcomes.

Example: "Washed Stain Scale" from 1 to 10.

1 = stain completely cleaned away (cannot see stain at all)

2 = only slight traces of stain can be detected upon close examination

and then continue 3, 4, 5, 6, 7, 8, 9 until ....,

10 = none of the stain was removed (can still see all of the stain)

NOTE: If you are not able to explain how to determine the answer through quantitative measurements, you must rephrase the question until you can.