Play with the Micrometer Model. Test what you've learned by trying the
input field.
Micrometers use the principle of a screw to amplify
small distances that are too small to measure directly into large
rotations of the screw that are big enough to read from a scale. The
accuracy of a micrometer derives from the accuracy of the thread form that
is at its heart. The basic operating principles of a micrometer are as
follows:
The amount of rotation of an accurately made screw can be
directly and precisely correlated to a certain amount of axial movement
(and vice-versa), through the constant known as the screw's lead. A
screw's lead is the distance it moves forward axially with one complete
turn (360°). (In most threads [that is, in all single-start threads], lead
and pitch refer to essentially the same concept.)
With an
appropriate lead and major diameter of the screw, a given amount of axial
movement will be amplified in the resulting circumferential movement.
The
micrometer has most functional physical parts of a real micrometer.
Frame
(Orange)
The C-shaped body that holds the anvil and barrel in
constant relation to each other. It is thick because it needs to minimize
expansion, and contraction, which would distort the measurement. The frame
is heavy and consequently has a high thermal mass, to prevent substantial
heating up by the holding hand/fingers. has a text 0.01 mm for smallest
division of instrument has a text 2 rounds = 100 = 1.00 mm to allow
association to actual micrometer
Anvil (Gray)
The shiny part
that the spindle moves toward, and that the sample rests against.
Sleeve
/ barrel / stock (Yellow)
The stationary round part with the linear
scale on it. Sometimes vernier markings.
Lock nut / lock-ring /
thimble lock (Blue)
The knurled part (or lever) that one can
tighten to hold the spindle stationary, such as when momentarily holding a
measurement.
Screw
(not seen) The heart of the micrometer It
is inside the barrel.
Spindle (Dark Green)
The shiny
cylindrical part that the thimble causes to move toward the anvil.
Thimble
(Green)
The part that one's thumb turns. Graduated markings.
Ratchet
(Teal)
(not shown ) Device on end of handle that limits applied
pressure by slipping at a calibrated torque.
This applet has an
object (Black)
with slider on left top to control the y-motion of
the object into the anvil and spindle (jaws), the graphics also allows
drag action.
with slider on left bottom to control the x-size of
the object into the anvil and spindle (jaws).
On the left bottom
slider is the zero error control to allow of exploring with if the
micrometer has either +0.15 mm (max) or -0.15mm (min) zero error. The are
check boxes:
hint: guide lines and arrows to indicate the region of
interest plus the accompanying rationale for the answer.
answer:
shows the measurement d = ??? mm
lock: allows simulating of the
lock function in real micrometer which disable changes to the position of
the spindle then by the measurement is unchangeable.
On the bottom
there is a green slider to control the position of the spindle, drag on
any part of the view also drags the spindle.
There is 2 buttons
left and right fine control to allow for single incremental change of the
measurement, to allow learners to sense the rotation simulation of the
spindle with the many lines to simulate the coarse pattern to increase
friction between fingers and on the thimble and ratchet.
The reset
button restores learning environment to default setting
Research
arXiv:1408.3803 [pdf] Vernier
caliper and micrometer computer models using Easy Java Simulation and its
pedagogical design feature-ideas to augment learning with real instruments Loo
Kang Wee, Hwee
Tiang Ning Comments: 8 pages, 8 figures, Physics Education journal Subjects:
Physics Education (physics.ed-ph); Instrumentation and Detectors
(physics.ins-det) https://youtu.be/jHoA5M-_1R4
(g) describe how to measure a variety of lengths with appropriate accuracy
by means of tapes, rules, micrometers and calipers, using a vernier scale
as necessary.