Mathematical Calculations in Science

Two basic types of calculations:

  1. Calculations that involve or use a formula equation - show your work following the steps outlined below.

    2. Four or five basic steps in showing your work:

    1. Write down the given information.
    2. Write down the formula equation in its usual form.
    3. Solve the equation for the unknown variable. (Physics & Chemistry only)
    4. Substitute into the equation the known values.
    5. Show the answer

    Example
    v = 56.5 mL
    D = 2.3 g/mL
    D = m/v
    m = D x v
    m = 2.3 g/mL x 56.5 mL
    m = 129.95 g

  2. Calculations that do not use a formula equation - show your work in smooth form.

Examples:

45.6 g ÷ 125.4 g × 100% = 36.36%

65 mi/hr × 5280 ft/mi × 1 hr/3600 s = 95.3 ft/s

Dimensional Analysis:

Dimensional analysis is a mathematical tool used to convert from one quantity to an equivalent amount measured in a different unit.  The basic format is as follows:

    Original Quantity x conversion factor = desired quantity

Examples:

How many feet is 2.4 miles?

    2.4 mi × 5280 ft/mi = 12673 ft

How many horsepower is 1250 watts?

    1250 W × 1 hp/745.7 W = 1.68 hp

How many cm is 100 yd?

    100 yd × 36 in/yd × 2.54 cm/in = 9144 cm