Barometers are tools used to measure air pressure, also called barometric pressure. We use them to predict weather based on rising or falling pressure. Rising pressure generally indicates that warm, calm conditions are ahead. Falling pressure generally indicates that cooler, stormy conditions are in the future.
Though some weather events (such as hurricanes, blizzards, and tornadoes) result from conditions on a fallen earth, Scripture is clear that God is in control. Genesis 8:22 says, “While the earth remains, seedtime and harvest, cold and heat, summer and winter, day and night, shall not cease.” Though we cannot know for sure what the weather will be from day to day, we can make educated predictions based on science.
There are two types of science: historical and observational. Historical science relies on interpretating evidence from past events with a philosophical point of view. Historical science is not observable, testable, or repeatable. On the other hand, observational science uses direct observation, the five senses, and the scientific method to explain a set of facts. Observational science is testable and repeatable.
We can use observational science to measure temperature, atmospheric pressure, and weather conditions on any certain day. A weather log is an example of using observational science. We can test, repeat, and record the data in a lab experiment. However, when meteorologists predict the weather for the following day or week, they are using historical science. Because they cannot directly observe what the conditions will be like, they base their predictions on past weather statistics, models, and data. The same goes for weather in the distant past. We can’t be certain unless we have records. We know there was a lot of rain and stormy weather about 4,300 years ago during the global flood described in Genesis 6–9. But how you interpret the past will depend largely on whether or not you believe God’s Word.
In this experiment, you can study the weather by building your own barometer.
As the air pressure changes outside the barometer, you will observe changes in the height of the pointer relative to the starting pressure inside the jar. For example, when the air pressure is high, the air outside the barometer will be exerting more pressure than the air inside the barometer. You may observe the balloon to be curved down into the glass jar, which will push the pointer above your starting point. The opposite effect will occur when there is low pressure. You may observe the balloon stretching upward, causing the pointer to be below your starting point on the chart.
Evangelista Torricelli, a pupil of Galileo, invented the first barometer in 1643.
When it was first invented, the barometer was a symbol of wealth and was used mostly as decoration in wealthy homes.