Measure student reaction times with these unique reaction time rulers precalibrated with reaction times to millisecond accuracy. The 28-page manual is filled with suggestions for experiments that measure the effects of medicines, foods and food additives; and human biorhythm patterns. Also included is information on graphing and performing statistical analysis of test results. In addition there is a discussion of common substances that can affect reaction times. Includes: 3 reaction time rulers; manual; copymaster for reaction time data sheets.