Estimation, Precision, and the SI Measurement System

These Q&A flashcards cover key concepts from the lecture on estimation, precision, the SI system, measurement units, prefixes, base and derived units, and fundamental properties such as length, mass, volume, and temperature.

What is estimation in measurement?

Using knowledge of something similar in size or amount to make a rough measurement of a new object.

When is estimation especially useful?

When you are in a hurry and exact numbers are not required.

What does precision describe in science?

How close repeated measurements are to one another.

How is accuracy defined in measurement?

How close a measurement is to the actual or accepted value.

Why do scientists worldwide use the SI system?

Because its measurements are easily understood by all scientists and are easier to convert than the English system.

List the three basic types of measurement in the SI system.

Length, mass, and volume.

Name four other common measurement types besides length, mass, and volume.

Time, temperature, density, and pH.

What is a standard in a measurement system?

An exact quantity that everyone agrees to use for comparison.

Give two examples of English-system length standards.

The yard and the inch.

Give two examples of SI length standards.

The meter and the centimeter.

What single number is the SI system based on?

10.

List the basic SI prefixes from kilo- to milli- in order.

Kilo, hecto, deka, (base) unit, deci, centi, milli.

What factor does the prefix ‘kilo-’ represent?

10³ (one thousand).

What factor does the prefix ‘centi-’ represent?

10⁻² (one hundredth).

Give the symbol and factor for the prefix ‘mega-’.

Symbol: M, Factor: 10⁶.

Give the symbol and factor for the prefix ‘micro-’.

Symbol: μ, Factor: 10⁻⁶.

Name the seven base SI units for length, mass, temperature, time, amount, luminous intensity, and electric current.

Meter (m), kilogram (kg), kelvin (K), second (s), mole (mol), candela (cd), ampere (A).

What is the derived SI unit and symbol for force (Newton)?

kg·m/s², symbol N.

State the formula and SI unit for density.

Density = mass/volume; unit kg/m³.

During SI conversions, what changes and what stays the same?

The decimal position changes; the digits themselves do not.

What must every measurement include?

A number and a unit.

Define length and give its basic SI unit.

The distance between two points; basic unit is the meter (m).

How is area calculated and expressed in SI units?

Area = length × width; expressed in squared units such as m² or cm².

Define mass and give its basic SI unit.

The amount of matter in an object; basic unit is the gram (g).

How are mass and weight related?

Weight is the pull of gravity on mass; greater mass means a larger gravitational pull.

How many grams are in a pound?

454 grams.

Define volume and state the basic SI unit used for liquids.

The amount of space an object occupies; basic unit for liquids is the liter (L).

What formula is used to find the volume of a rectangular solid?

Volume = length × width × height (units³).

What method can determine volume of irregular objects and what key equivalence applies?

Water displacement; 1 milliliter (mL) equals 1 cubic centimeter (cm³).

What does temperature measure at the particle level?

The kinetic energy of atoms in a substance.

What are the freezing and boiling points of water on the Celsius scale?

0 °C (freezing) and 100 °C (boiling).

At what value does the Kelvin scale start, and how is Celsius converted to Kelvin?

Starts at absolute zero (0 K); Kelvin = Celsius + 273.