How to read a barometer?

My mom bought a barometer with the floating balls because it was pretty, how do you read it?

• the balls are labeled and filled with diffrent colored liquids and it was boghut at an auction so there was no instructions. weather is a hobby we share/

• Answer:

  The average atmospheric pressure is one kilo per square centimeter. Well, that is if the average pressure was 1,000 hPa but it is in reality 1,013.25. That is also called one atmosphere or one Bar. Water on the surface is also subject to that pressure and when it increases, the water pressure increases too. If you have balls, or anything to a density very close to that of the water, those will sink or rise as their own density is more or less that of water. In that way, you can see the atmospheric pressure by counting how many balls are floating and how many are at the bottom. In a very high pressure, all the balls will be at the bottom. Enjoy meteorology with your mom. At the age of 60, this is still my favourite hobby that started as a child with my father, an airman that was teaching meteorology to pilot students. The fun with meteorology is that it changes every day and is never the same! :-)