Beacon Lesson Plan Library

Reaction Time

M Dennis


This lesson helps the student collect, organize and analyze data while studying reaction time. Students calculate measures of central tendency using a calculator and show data on graph.


The student analyzes real-world data by applying appropriate formulas for measures of central tendency and organizing data in a quality display, using appropriate technology, including calculators and computers.


-Metric rulers
-Teacher-made worksheets (see attached file)
-Pencils for students to record data


1. Compose and make copies of worksheet
2. Gather metric rulers and calculators


This activity can be used after studying the Measures of Central Tendency and /or during Red Ribbon Week to explain reaction time.

1. Lead a class discussion of reaction time
a) What is reaction time?
b) Why does it vary?

2. Review the measures of central tendency:
a) Mean is the sum of the numbers divided by the number of numbers.
b) Mode is the number that occurs the most.
c) Range is the difference between largest and smallest numbers.

3. Divide the class into groups of two students.

4. Give each group a metric ruler.

5. Pass out teacher-made worksheets. (See attached file.)

6. In each group, student A holds ruler vertically with hand on the 30cm end. Student B, whose reaction time is being measured, places his hand under the ruler. Student B will place his thumb and forefinger 2 centimeters to either side of the 0-mm mark on ruler. Student A drops the ruler and student B looking only at the bottom of the ruler catches the ruler. To catch the ruler student B presses his thumb and forefinger together as quickly as possible.

7. To measure the reaction time for stopping the ruler, use the first millimeter mark that is just above the thumb. This reading will be an indication of the reaction time. The fastest reaction time will be the lowest number. For example, a score of 130 mm means a faster reaction time than a score of 155 mm.

8. Each student repeats the process five times.

9. Give the groups 40 minutes for the students to complete drops and record information.

10. Students share their results in a teacher directed discussion.

11. Record all the results on the board.

12. Each student also records all class members' means on the worksheet.

13. The student is given 25 minutes to complete worksheet.

14. The students can visit Mr. Warner's Cool Science Web site to measure their reaction time on the computer for an extension of this lesson.


1. The formative assesmentis based on the number of correct answers.
a) Individual mode is correct
b) Individual mean is correct
c) Individual range is correct.
d) Classroom mean is correct.
e) Graph is complete.
Students who do not have their answers correct need additional feedback and practice time.

2. Teacher observation
a). During teacher interview the student adequately explains the difference between mean, mode, and range.
b). The student demonstrates his use of the calculator by solving the problems on the worksheet correctly.
c). Each student takes a turn dropping the ruler and recording data.
d). Each group gives results for the class discussion.

Web Links

Additional information is provided.
Mr. Warner's Cool Science: Reaction Time

Attached Files

A document created for students to record reaction times.     File Extension: pdf

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