| At that moment, when the liquid turns a little above the rubber tube, it is necessary to block the tube clamp and stop heating the gas in the flask. The gas temperature will drop, but regardless of this level of fluid in the gauge will not change, as previously existing, knee manometer was closed and the atmospheric pressure in the knee does not affect the fluid. Device into a sealed pressure gauge with a knee - the closed manometer. Similar gauges typically measure small pressure. Fluid in a closed knee goes down only after pressure in the associated vessel will be less difference between the height of liquid column in manometer knees. It is understandable that with very little cooling of the flask the gas pressure changes very little, so the gauge will remain the same level of the liquid. 5. Balloon. Desirable to have an analytical balance. Balance beam to produce a better wire length of 400 mm and a diameter of 4-5 mm. Balloon glue starch glue strips of tissue paper. To the strip were the same, you should make a pattern from construction paper and using them to cut out twelve segments of the ball of tissue paper. First glue the two segments together. From these six "boats" glue the three parts of the world (in each of four strips). Then begin to stick together all the world. Open at the bottom of the ball must be double-glued strip of paper, inside and out. Of tissue paper, folded in half, cut a circle with a diameter of 50 mm. Threading through the center of the circle strong thread. One end of the thread is glued to the circle, and then paste it to the pole of the ball. With the help thread the ball hung in the balance beam and balance scales. Now, if a balloon to put the stove (not very close, otherwise it could catch fire), the equilibrium is disturbed balance. This is explained by the fact that the heated air is lighter than cold, so he picks up a balloon. 6. Small bottle be filled with three-quarters of densely colored water. Then pick up cork or rubber stopper, which should be tightly closed bottle. In a traffic jam and make a small hole through it pass through the glass tube is possible with a smaller diameter drawn ending. The lower end of the tube should reach almost to the bottom of the bottle and the top should be slightly above the tube. With this device you can do some interesting experiments. First experience. Put the bottle in a container with hot water. After some time out of the bottle begin to beat the fountain. The second experience. Put the glass a few sheets of filter paper soaked with water. On paper, put the bottle and cover it with a glass jar, previously well heated. Bottle opening press more tightly to the wet paper. After some time out of the tube begins to beat the fountain. Explain the observed physical phenomenon is very simple. In both experiments, the air trapped in the bottle above the liquid is heated, its pressure increases and the fluid starts hitting the fountain. |