Reaction Time Ruler Drop Test

Here is a simple reaction time test using only a ruler, and a little bit of calculating. This is a good science class project. This test uses the known properties of gravity to determine how long it takes a person to respond to the dropping of an object by measuring how far the object can falls before being caught. An even simpler test, a variation of this test but not involving any calculations, requires making your own Reaction Timer. There are some commercially available variations of this test - see this review of Reaction Sticks.

test purpose: to measure reaction time, hand-eye quickness and attentiveness.

equipment required: 1 meter long ruler or Yardstick, calculator.

pre-test: Explain the test procedures to the subject. Prepare forms and record basic information such as age, gender and test conditions. Write down which is the preferred hand. See more details of pre-test procedures.

procedure: The person to be tested stands or sits near the edge of a table, resting their elbow on the table so that their wrist extends over the side. The assessor holds the ruler vertically in the air between the participant's thumb and index finger, but not touching. Align the zero mark on the ruler with the participant's fingers. The participant should indicate when they are ready. Then, without prior warning, the assessor releases the ruler and lets it drop - the subject must catch it as quickly as possible as soon as they see it fall. Record in centimeters the distance the ruler fell (the level the participant grabs the ruler). Repeat this procedure several times (e.g. 10 times) and take the average score.

Calculator:

Calculate the average distance the ruler fell and enter it in this form

Table: You can also use the table below to determine how long it took the ruler to fall the measured distance (distance in cm, time in seconds).

distance (cm) time (seconds) distance (cm) time (seconds)
1 0.045 51 0.323
2 0.064 52 0.326
3 0.078 53 0.329
4 0.090 54 0.332
5 0.101 55 0.335
6 0.111 56 0.338
7 0.120 57 0.341
8 0.128 58 0.344
9 0.136 59 0.347
10 0.143 60 0.350
11 0.150 61 0.353
12 0.156 62 0.356
13 0.163 63 0.359
14 0.169 64 0.361
15 0.175 65 0.364
16 0.181 66 0.367
17 0.186 67 0.370
18 0.192 68 0.373
19 0.197 69 0.375
20 0.202 70 0.378
21 0.207 71 0.381
22 0.212 72 0.383
23 0.217 73 0.386
24 0.221 74 0.389
25 0.226 75 0.391
26 0.230 76 0.394
27 0.235 77 0.396
28 0.239 78 0.399
29 0.243 79 0.402
30 0.247 80 0.404
31 0.252 81 0.407
32 0.256 82 0.409
33 0.260 83 0.412
34 0.263 84 0.414
35 0.267 85 0.416
36 0.271 86 0.419
37 0.275 87 0.421
38 0.278 88 0.424
39 0.282 89 0.426
40 0.286 90 0.429
41 0.289 91 0.431
42 0.293 92 0.433
43 0.296 93 0.436
44 0.300 94 0.438
45 0.303 95 0.440
46 0.306 96 0.443
47 0.310 97 0.445
48 0.313 98 0.447
49 0.316 99 0.449
50 0.319 100 0.452

The table is based on the following formula, where d = the distance the ruler fell in meters, g = the acceleration of gravity (9.8 m/s2), and t = the time the ruler was falling (seconds)

t = √ (2d / g)

scoring: There is a scoring table on the make your own Reaction Timer page where you can rate your score.

target population: sports requiring good hand-eye coordination and quick reactions, such as race car driving, boxing and racket sports.

variations: you could adapt this test to determine the reaction time to a sound, by using the set up with the subject wearing a blindfold, and the ruler being released at the same time as an auditory signal.

comments: results for left and right hands can be expected to be different, therefore this should be controlled for or at least the hand used recorded with the results.

Testing Extra

We have over 400 fitness tests listed, so it's not easy to choose the best one to use. You should consider the validity, reliability, costs and ease of use for each test. Use our testing guide to conducting, recording, and interpreting fitness tests. Any questions, please ask or search for your answer.