Manual

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35. Reed Switch
Build the circuit, move the magnet (7) towards the reed
switch (83), the alarm (78) will sound while the LED (69)
is on. Move the magnet (7) away, the alarm (78) and LED
(69) will turn off.
Reed switch circuits like this can be used to detect uid
levels for coffee makers, dish washers, washing machines
and water heaters. By putting a magnet on a oat, which
rises and falls with the liquid in the container, the magnet
can trigger a reed switch circuit that sets off an alarm
and lights whenever the liquid, and by extension, the
magnet, reach a certain level.
36. Newton’s Second Law of Motion
Build the circuit, press the switch (62), then hold the press
switch (61). The fan blade (60) of the motor (95) will spin.
Release the press switch (61), the fan blade (60) will launch
into the air. (Caution! Never let it y near your face!)
If the fan does not y, make sure the batteries are fresh,
the motor (95) is in the correct direction, and give the
fan a tap from underneath with the top of your ngernail.
This circuit demonstrates Newton’s Second Law of Motion:
acceleration is produced when a force acts on a mass. In
this case, air pressure under the fan blade forces it to rise.
Reminder: Remove the shaft cap before
using the ying saucer.
WARNING: Moving parts. Do not touch
the fan or motor during operation. Do
not lean over the motor.
!