Science with the Crumble: Test your reactions

HYPOTHESIS: Humans react more quickly to something they hear compared to something they see.

In order to test this hypothesis, we used:

  • Laptop with Crumble software installed
  • Crumble controller & Sparkle baton
  • Crumble-friendly battery box; 3 AA batteries
  • Croc-leads and a micro-USB cable
  • “Crumble-friendly” switch and buzzer

The Crumble, Sparkle baton, switch and battery box are connected in the same way as the last reaction timer project (although the switch is connected to input A, rather than B). The program, however, is much simpler:

At the start, all the Sparkles are turned off. The Crumble waits for a random period of time (between 2 and 6 seconds) and then begins lighting the Sparkles in quick succession (every 50 milliseconds). The aim of the game is to press the switch as quickly as possible. Note: you have to hold down the switch until you have read your “score”. When the switch is released, the game restarts. Joseph & I discovered that, after a bit of practice, we could consistently press the switch after 4 or 5 Sparkle LEDs had lit up (i.e. after 150-200 milliseconds). 

In order to test whether we could react more quickly to a sound, a buzzer was then connected between “output B” and “Ground” (a “-” pad on either the battery box, or the right-hand side of the Sparkle baton). The program was modified so that the buzzer turns on at the same time as the first Sparkle LED:

For a fair test, you have to close your eyes while playing – but remember to open them and read your score before releasing the switch! Now we found that we could press the switch after 3 LEDs were lit (100 ms). 

So, our small sample does support the hypothesis, above. Further reading suggests that humans react even faster to touch-stimulus: can you think of a way to measure that with the Crumble? If you do the experiment with a larger group, let us know your results and we will publish them, here!


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