The barometers are instruments used to measure ambient pressure and predict, in a way, whether there will be precipitation or a climatic disturbance. In this article, we will see how to make a homemade barometer, with which we can keep track of changes in ambient pressure where we are.
- A glass jar with a wide mouth.
- A balloon.
- An elastic band.
- A straw, the longer the better.
- A sheet of paper.
Arming the barometer
The first step in setting up the barometerThe first step is to inflate the balloon and then deflate it, so that it stretches and becomes more sensitive to variations in pressure. Then, with the help of a pair of scissors, cut the balloon into two parts, discard the lower part and keep the round part of the balloon.
Next, we take the top (round) part of the balloon and cover the mouth of the glass jar, fixing the piece of balloon with an elastic band. Make sure that the bottle is hermetically sealed and that no air enters or escapes.
Once the bottle is hermetically sealed with the piece of balloon, cut the ends of the straw obliquely with the help of a scissors and fix one of its ends (using glue) in the centre of the membrane created with the piece of balloon.
Our barometer is ready, now all we have to do is place it near a wall where we have previously placed the sheet of paper. On the sheet of paper, we mark where the free end of the straw is and take measurements at different times of the day and for several days, to visualise the changes in the temperature. pressure of the environment where we have placed our barometer.
How it works
The barometer that we have constructed works like this: the elastic membrane that we create with the balloon registers the changes in ambient pressure by assimilating the force, as if we were beating a small drum.
Each time the pressure increases, the force on the membrane increases and the straw rises in level by means of the leverage effect, showing a higher mark on the recording paper. On the other hand, if the pressure decreases, we will see that the mark on the straw is much lower. We can observe that on rainy days, the pressure will be lower than on dry days.
This barometer The home-made weather forecaster will be of great help to predict the weather in a superficial way and can also be used in a science project.