Question | Answer |
standard of measurement | an exact quantity that people agree to use for comparison |
examples of standard measurement | hands, an arm's length, feet |
two basic systems of measurement | English and metric system |
Why is metric system used in science? | all SI standards are universally accepted and understood by scientists |
System most commonly used in United States | English system |
SI is the standard system used worldwide | Metric system |
two sources of error when making measurements | equipment/ instrument error and human error |
basic unit of length in metric system | meter (m) |
What are more common prefixes for measuring length? | centimeter (cm), millimeter (mm), kilometer (km) |
What piece of equipment is used to measure length? | ruler, meter stick |
Two rules for measuring length accurately? | use metric side of ruler, begin reading at first mark (not edge of ruler) |
Distance around the outside of a figure | perimeter |
formula for perimeter | p= s + s + s + s |
label for perimeter | cm |
area | amount of surface space |
formula for area | A= l x w |
label for area | cm squared |
volume | amount of space an object takes up (occupies) |
formula for volume | V= l x w x h |
label for volume | cm cubed or cc |
mass | the amount of matter in an object (molecules) |
basic unit of mass in metric system | gram (g) |
common prefixes used for mass | milligram (mg) and kilogram (kg) |
Balance | piece of equipment used to measure mass |
tare weight | the weight of paper or container |
3 rules for using balance accurately | carry using two hands, never place chemicals directly on balance, slide weights to zero before removing object |
weight | the pull of gravity on the object |
metric unit for measuring weight | Newtons (N) |
spring scale | piece of equipment unsed to measure weight |
difference between mass and weight | weight can vary depending on the pull of gravity |
liquid volume | amount of space an object takes up |
basic unit of liquid volume | liter |
common prefixes for liquid volume | milliliter (ml) |
piece of equipment used to measure liquid volume | graduated cylinder |
Why are beakers and flasks not use- need to determine volume | their results are not accurate |
meniscus | curvature of the liquid due to surface tension and capilllary action |
2 rules for measuring volume accurately | Place on flat surface and read at eye level; take reading from the bottom of meniscus |
water displacement | when an object is placed in water, the object's volume is equal to the amount of water displaced |
volume of jagged stone | Fill graduated cylinder part way. Take reading and record. Add object slowly. Take reading and record. Add object slowly. Subtract first reading from second. |
density | mass per unit volume of a material (amount of molecules in a given space) |
3 pieces of equipment needed to find density | balance (mass), ruler, or graduated cylinder (volume) |
formula for density | D= m/v, M= V x D, V= m/d |
label for density | g/cm3 or g/cc or g/ml |
density for water | 1 gm/cc |
density of cork | 0.3 g/cc |
copper | 8.9 g/cc |
What determines if an object will float or sink? | its density compared to that of water (1 g/cm3) |
If an object floats | its density is less than water |
If an object sinks | if its density is more than water |
Does density change? | No, it's a constant |
Temperature | How hot or cold an object is- relates to the speed of molecules |
3 temperature scales | degrees F, C, K |
Which is the SI unit of temperature? | degrees K |
Equipment used to measure temperature? | thermometer |
boiling/condensation point of water | 212 F degrees, 100 C degrees, 373 K degrees |
freezing/melting point of water | 32 F degrees, 0 C degrees, 273 K degrees |
absolute zero | -459.4 F degrees, -274 C degrees, 0 K degrees |
body temp | 98.6 F degrees, 37C degrees, 310 K degrees |