It is not always possible to buy a barometer, so I want to propose the design of a home barometer, which will show atmospheric pressure with some accuracy.
The barometer (see figure) consists of a bottle with transparent glass, a glass tube and cork. One-third of the bottle is filled with water, it is better to take distilled water, because the usual blooms in a year. Water can be slightly tinted. A hole is made in the cork into which a glass tube is inserted. The junction is covered with plasticine. Now it remains to plug the bottle with a stopper. The barometer is ready. When atmospheric pressure begins to change, the water level in the tube will change. If air bubbles start to come out of the tube, then the pressure is very high, and this is to clear stable weather, at such a time there is a good bite. If water begins to pour out through the top of the tube, the pressure is low, you can wait for the storm, but you should not go fishing.
The simplest do-it-yourself barometer
Such a barometer can be made of a small tin oiler with parallel sides.
Pick a cork that would tightly close the only hole of the future barometer. Before you put the cork in place, you need to make a hole of such a diameter in it that a transparent tube-straw for cocktails is passed through it. However, it is better to use a glass tube with an inner hole diameter of 1.5 - 2.0 mm.
The 2/3 capacity is filled with tinted water, a tube with a stopper is inserted into the hole, while
should contain a little of the same tinted water. With increasing atmospheric pressure, the liquid level in the tube will rise, and vice versa.
Fix such a barometer on a stand with a vertical ruler. You can calibrate it by taking readings from a real barometer.
Instead of a metal container, you can use any small glass bottle. After filling with tinted water and installing the tube plug, add some water to the tube. Since the body of the barometer is rigid, with increasing pressure the water level will decrease, with decreasing it will increase.
Light bulb barometer
Take a blown out light bulb and where the base with the threaded part starts, carefully drill a small hole with a diameter of 2-3 mm. This should be done very carefully, otherwise the balloon may crack or break.
Here is the easiest way to drill glass. At the point where you marked the hole, apply a drop of machine or sunflower oil. Take abrasive powder from medium-sized sandpaper and sprinkle it on an oil drop to make a viscous paste that is slightly softer than a toothpaste. Then clamp the copper wire in the drill chuck. Its diameter should correspond to the size of the hole you want to drill. Grip the lamp base gently. And wrap the glass flask with a towel or rag. Drilling must be done very carefully with minimal effort.
When the hole is drilled, fill it with tap water, filling the glass flask to half. Then add two to three drops of ink or a slice of the chemical pencil lead and mix. The barometer is ready.
It remains to wait until the inner wall of the flask dries, and hang the barometer between the window frames. It is best from the north side, where direct sunlight will not fall on it. If the windows face south, install at the top of the window. After a few hours, you can take readings. Our barometer can predict the weather for a day quite fully. Continuous or variable cloud cover awaits us, or it will rain, light, lingering, short-lived, maybe thunderstorm ...
True, you need to know some features in order to decipher the testimony:
If the inner walls of the bulb are covered with small drops of condensed water - tomorrow there will be overcast, but without precipitation.
If the walls of the bulb are covered with droplets of medium size, and between them vertical dry stripes formed - variable cloud cover.
and the walls are partially covered with large drops of dew - wait for short-term precipitation. And from top to bottom, and drops, enlarging, flow down - there will be a thunderstorm.
Large drops are only near the surface of the water, and the neck of the bulb is dry - the rain will pass sideways, 30-60 km from your places.
It was raining outside, and the walls of the light bulbs became completely dry, without fog and droplets - tomorrow the weather will be fine.
And if dew drops appeared only on the north side of the bottle, wait for rain tomorrow afternoon.
Of course, you can use such a barometer only if the air temperature is above zero, that is, in spring, summer and early autumn.
Do you remember? You can now surprise homeworkers and compete with professional meteorologists.