Data Sheet

-24-
WARNING: Moving parts. Do not touch
the fan or motor during operation. Do
not lean over the motor.
!
7. Newton’s Second Law of Motion
Remove the cap (60A) that is on the fan blade (60). Hold the press
switch (61) for ten seconds. Release the press switch (61) and the ying
saucer should take off (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.
8. Magnet-controlled Flying Saucer
Replace the press switch (61) with the reed switch (83) and move the
magnet (7) towards the reed switch (83). Wait for a few seconds then
move the magnet (7) away to launch the saucer. A reed switch is typically
made from two or more ferrous reeds encased within a small glass tube-
like envelope, which become magnetized and move together or separate
when a magnetic eld is moved towards the switch.
9. Reversing the Motor
Install the motor (95) in the reverse direction (i.e. so the 95 is near the
top instead of near the bottom) and move the magnet (7) towards the reed
switch (83). This time when you move the magnet (7) away the fan (60)
does not launch. This is because by installing the motor (95) reversely, the
motor (95) shaft spins in the opposite direction which makes the force on
the fan (60) blade push the fan in the downward direction.
10. LEDs in Series
Build the circuit shown on the left and turn on the switch (62). The
heart LED (69) and the star LED (70) will both light (make sure both LED
modules are in the circuit in the correct direction based on the markings
show in the diagram), but they are both dim. This is because these
LED modules have internal resistance built into them to protect from
too much current going through the LED and burning it out. By placing
the heart LED (69) and star LED (70) in series like in this circuit, there
is only a single path for current to ow from the 4.5V terminal of the
battery (91) to the “–” terminal of the battery (91), which is through both
LED modules. Thus the current in this circuit is limited by the sum of the
internal resistances of each LED module, which is why the LEDs are dim.
Reminder: Remove the shaft cap (60A)
before launching the ying saucer.