| 7. On a wooden rack in a vertical reinforcing metal clip with. Between him and the end of the arrow D pull nichrome wire length 400-500 mm (it can be taken from an old burned-helix Hotplates). The arrow must be easily rotated around the axis O. In-circuit electric current voltage 10.12 volts and the wire became longer. Therefore, the arrow will go down on the scale of a few units. To increase the sensitivity of the instrument short arm direction should be as small as possible. At zero scale division shooter set moving clip with a vertical rack (clip clip, or should have to move with greater friction). 8. At the base length of 500 mm and a width of 80 - 100 mm strengthen two racks in height 200-250 mm. They need to put in the form of electrical poles or telegraph line. Between the "poles" stretched rectilinear wire of burned-out coil from an electric tile. By wire supplied current, and by heating it provisnet. Especially well visible sag when to pull the two wires, and the current pass through one of them. Remain strained, and the second wire will show the value of the first wire sagging. Instead of the two wires can pull the wire through which will pass current, and a white thread. The device is included in the network voltage of 10 - 12 volts. 9. Two thin plates of different (eg, iron and copper) with a length of 60-100 mm are added together. They drilled through holes at a distance of 10-15 mm from each other. In the hole to insert copper rivets and rasklepat them with a hammer, the platelets adhere properly to each other. The resulting disc is composed of two metals having different coefficients of linear expansion, so if it is heated, it will bend more strongly, the greater the difference in coefficients of linear expansion made of metals and the higher the temperature of heating. Students should tell you that the album, consisting of two metals, said bimetal. If a bimetallic plate at one end to nail to the counter, and the other end of it to attach a light arrow, then when heated, even a match flame bend plate, and the arrow moves along the scale. If the cooling plate, for example, dry ice, it deviates in the opposite direction. Sensitivity of the device increases with decreasing mass and size of the plate. |