PASCO Specialty & Mfg. DISCOVER DENSITY SET SE-9719 Manual De Usuario

012–07192A

Discover Density Set

This sample problem presents you with experimental data, and then leads you

through a process to obtain an equation that relates the data.  A similar problem

based on the materials in this set is left for you to do, based on the same

process.  The method is then extended to more complex situations.

A lightning bolt struck the earth, and upon seeing it, a number of observers

started timing, using stopwatches.  The observers each stopped their watches

when they heard the thunder.  The times recorded, and the distances of the

observers from the point the lightning struck are recorded in the table.  The

variables have arbitrarily been labeled x and  y:

     y

 time

distance

  (s)

   (km)

  3.7

   1.2

  5.2

   1.8

  8.3

   2.8

12.1

   4.1

14.9

   5.1

When this data is graphed, a straight line can be drawn that closely

approximates the pattern of the data.  We may assume that there are errors in

the data caused by factors such as  random differences in human reaction time

in actuating the stopwatches, and inaccuracies of an unpredictable nature in

measuring the distances.  Such errors may be the reason that the points do not

all fall exactly on the line.

A c t i v i t i e s

Figure 2
Graph of Speed of
Sound data