PHYSICAL SCIENCE A NOTES

 

HOW TO USE A BALANCE

 

To measure out x grams of a a powdery chemical:

  1. mass out the empty container (beaker, massing cup, flask, etc.)

  2. move the riders over x grams (so if the cup was 2.25 g, move the riders to 2.25 g + x)

  3. use a clean scoop to slowly add chemical to the container until the pointer points to zero

MSDS SHEETS


An MSDS sheet tells about the hazards of a chemical.

  • stands for Material Safety Data Sheet

  • lists the hazards and properties of a chemical

  • located in the black binders in room 1403

  • part of state and federal "right to know" laws

TYPES OF DATA

 

Data is everything you see, feel, hear, and measure during lab.

 

There are two types of data:

  • qualitative = descriptions (words and pictures)

  • quantitative = measurements (numbers)

DESCRIBING MEASUREMENTS

 

There are two ways to describe a good measurement:

  • precise = repeatable

  • accurate = correct

The goal of a scientist is to have measurements that are both precise AND correct.

 

TEMPERATURE

Temperature:

  • Temperature is the average kinetic (moving) energy of the atoms
  • It is measured with a thermometer
  • There are 3 temperature scales: Fahrenheit (US), Celsius (SI - used throughout the world), and Kelvin (SI - used in science)
      •  
      Kelvin*
      Celsius
      Fahrenheit
      Temperature of...
      373 K
      100 °C
      212 °F
      boiling water
      310 K
      37 °C
      98.6 °F
      body temperature
      273 K
      0 °C
      32 °F
      water freezing
      0 K
      - 273 °C
      - 459 °F
      coldest possible
        *NOTE:
          Kelvin is Celsius + 273.  All Kelvin temperatures are positive because it starts at absolute zero.  Absolute zero is the coldest possible temperature, where all atoms stop moving.