The stroboscope is the device allowing to observe discrete elemental motions of quickly moving objects. Such device can be used at physics lessons when studying various mechanisms. It will be useful and at a physical education class when studying elemental motions of the athlete. The principle of operation of the self-made stroboscope is based that the subject is observed through periodically blocked opening (shutter).
It is required to you
- Wooden bar 20-25 cm long, thickness and 5 cm wide
- Electric motor of a direct current
- The food battery to the electric motor
- Variable resistance (resistor wire) with a full resistance of 5-25 Ohms
- 2 pieces of plywood 20х20 cm
- Switch
- Assembly wire
- Screws
- Small pieces of dense polyfoam 2-3 mm thick
- Glue "Moment"
- 2 small nails
- Adhesive tape or insulating tape
- Tools:
- Screw-driver
- Drill
- Drills
- Fret saw
- Compasses
- Ruler
- Knife
- Emery paper
- Hammer
Instruction
1. Cut out a disk with a diameter of 20 cm from plywood. On this disk from the same center draw a circle with a radius of 5 cm and 8 cm. Carry out through them the general diameter. Divide an internal circle into 6 parts. In a point of intersection of an external circle with the general diameter drill an opening with a diameter of 1 cm of 6 same openings drill on an internal circle according to a marking. In the center of the received disk drill an opening with a diameter of 1 mm (the opening has to be less than diameter of an axis of the engine).
2. By means of a small nail beat a disk to the second plywood blank so that the nail was easy to be taken then. Hammer a nail, having combined the centers of a disk and preparation. Hammer the second same nail into the received preparation in any point, far away from openings. It is not necessary to punch the second sheet of plywood up to the end.
3. Using a disk as a cliche, mark and drill one opening on an external circle and on internal, from the opposite side of diameter of a disk. Circle a disk and separate details. Cut the second disk on a contour.
4. Manufacture the device handle of wooden bar. It is intended for fastening of the engine. That is on the one side of the handle make sample under the engine so that it was possible to fix it not movably by means of, for example, tin plate. After you fix the engine on the handle, solder to it withdrawal of wires.
5. On the center of a disk with a large number of openings paste a small foam or rubber washer. Diameter of a washer can be about 2 cm. Densely with a tension fix a disk on an engine axis, having strengthened connection by glue.
6. Collect the electrical circuitry, having consistently connected the electric motor, the resistor, the switch of food and the battery of food. Details can be fixed on the handle by an adhesive tape or an insulating tape so that they did not prevent rotation of a disk.
7. By means of screws not movably fix the second disk on the handle so that the centers of both disks coincided, and through both openings of a motionless disk at rotation mobile it was possible to see openings of another.
8. It is possible to start observations. Having turned on the electric motor, observe the studied subject or the mechanism through one of openings of a motionless disk and an opening of a mobile disk. Strobirovaniye frequency at observation through an opening of an internal circle will be more and is suitable for observation of faster processes. For observation of slower processes use external "window". Besides, the frequency of rotation of a disk can be regulated smoothly variable resistance.