Qualitative Observations
Changes in color and physical state
Quantitative Measurements
Involve numbers based on the SI metric system
Stating a Measurement
In every measurement there is a number followed by a unit from a measuring device
Length SI Unit
Meter (m)
Mass SI Unit
Kilogram (kg)
Time SI Unit
Seconds (s)
Temperature SI Unit
Kelvins (K)
Derived SI Units
Produced by dividing or multiplying standard SI units;
area: m�
volume: m�
density: g/cm�
Kilo
Means 1000 of that unit; 1 kilometer is 1000 meters
Centi
Means 1/100 of that unit; 1 meter is 100 centimeters
Milli
Means 1/1000 of that unit; 1 Liter is 1000 militers
Scientific Notation
A way of expressing really big numbers or really small numbers; Consists of two parts: A number between 1 and 10, and a power of 10
Standard Form to Scientific Notation
1. Place the decimal point so that there is one non-zero digit to the left of the decimal.
2. Count the number of decimal places the decimal has "moved" from the original number This will be the exponent of 10
3. If the original number was less than 1, then the exponent is negative; if the original number was greater than 1, the exponent is positive
Scientific Notation to Standard Form
1. Simply move the decimal point to the right for positive exponent 10
2. Move the decimal point to the left for negative exponent 10. (Use zeros to fill places)
Fahrenheit
Based on human body; 212� (boiling point of water); 32� (Freezing point of water)
Celsius
Based on freezing and boiling point of water; 100� (boiling point of water); 0� (freezing point of water)
Kelvin
Based on the movement of particles; 373 (boiling point); 273 (freezing point);
Temperature Calculation
K = �C + 273
(Ex:) Body Temp. = 37�C + 273 = 310 K
Dimensional Analysis Steps
1. Identify starting and ending units
2. Line up conversion factors so units cancel out
3. Multiple all top numbers and divide by each bottom number
4. Check units and answer
Mass
Amount of matter (grams, measured with a balance); Always continuously the same
Weight
Force exerted by the mass, only present with gravity (pounds or Newtons; measured with a scale)
Density
The ratio of mass to volume; An important and useful physical property; mass (g)/volume (cm�)
Density Problem Solving Method
1. List the given information
2. State the unknown.
3. Write the formula, rearrange to solve for the unknown
4. Plug in numbers with units
5. Calculate and box answer with units
Volume
The amount of space occupied by an object
Volume Displacement
A solid displaces a matching volume of water when the solid is placed in water; (With liquids, substance with highest density will sink)
Accuracy
How close you are to the actual value; Depends on the person measuring
Absolute Error Equation
| measured value ? actual value |
% Error Equation
| measured value ? actual value | / actual value ? 100
Precision
How finely tuned your measurements are or how close they can be to each other; depends on measurement tool, determined by number of significant digits