Instructions

19
Game and Knowledge in Electronics-Lab
When light flashes up somewhere, the photoreceptors in the eye
are stimulated and signal this information to the brain. This stimulus
remains for about a tenth of a second and then fades. Film works
in the same way. Individual images are shown so quickly, that we
don’t see them as being individual. For the first cinematic movies,
16 images per second were sufficient. But you can see some
flickering. Today’s films are shown with 24 images per second. The
frequency was increased to 50 images per second for television.
In the centre of the field of vision,
we see sharp images, but
slowly while the areas
around it are more
blurred, but we see
them faster. So, if you
look at the LED when
it’s on your side, you
can see the flickering
much more clearly. Some
animals can see much,
much faster movement than we can.
Some insects can even detect up to
300 images per second.
15
Once everything is securely fastened to your mounting plate, you
can wave the entire constructions back and forth. Doing this, you
can draw a red dashed line in the air. The red flashes turn into red
stripes in the air. This happens because short light pulses continue to
have an effect in the eye. If you set a higher flashing frequency, the
stripes will be shorter. If you make the flashes longer, the stripes will
also be longer.
Red stripes in the air