Barometric Mason Jar
Introduction: Barometric Mason Jar
Weather an everyday preoccupation over which we have no control but affects our daily lives in so many ways.
How do we know what the weather will be like from day to day, check the weather bulletins, look out of the window or monitor it yourself.
Using a STEAM approach you can create basic tools to aid in weather forecasting.
Science - Any system of knowledge that is concerned with the physical world and its phenomena and that entails unbiased observations and systematic experimentation.
Technology - Methods, systems, and devices which are the result of scientific knowledge being used for practical purposes.
Engineering - Scientific principles to design and build machines, structures, and other items.
Arts - The expression or application of human creative skill and imagination,
Mathematics - The abstract science of number, quantity, and space,
We will be observing the effects of the weather by using a device that responds to atmospheric pressure and by gathering and analysing the data gain an insight into the relationship between the two.
One simple method to monitoring atmospheric pressure is a Barometer were we can get an indication of the likely weather conditions.
Barometer, a device for measuring atmospheric pressure and predicts changes in the weather.
Atmospheric pressure equates to 1.03 kilogram force per square centimetre, though in reality its affected by weather conditions, altitude and temperature.
There are may types of Barometers but the simplest and earliest forms are water based.
This Instructable will focus on a water based Barometer, although the aneroid variant could also be made.
Our simple water based Barometer is not an absolute indicator of weather being a gauge but can complement other data such as wind direction and temperature to provide a more informed assessment.
Supplies
Mason Jar
Clear or translucent plastic tube or Straw
Water
Food Colouring or Dye (Optional)
Grommet and/or Silicone sealer.
Drill bit (slightly larger then the straw to enable the grommet to be fitted and create a snug fit when the straw is inserted.).
Short ruler.
PTFE tape
Step 1: Methodology
How does the Barometer work.
It works on the principle of pressure differential.
The difference between the air pressure in the upper part of the jar compared to the atmospheric pressure pushing down on the exposed end of the straw. Hence the reason for leaving the end of the straw open.
As the atmospheric pressure increases a force is exerted on the end of the straw which pushes the water this then applies pressure inside the jar trying to compress the air in the upper part of the jar.
As the atmospheric pressure decreases the force exerted on the end of the straw reduces, the opposing force from inside the upper part of the jar pushes against the water and the level rises.
These changes in atmospheric pressure coincide with the weather conditions, higher pressure for more favourable weather and lower pressure for more inclement weather.
Therefore by monitoring the level of the water in the straw we can get a determination of the atmospheric pressure and from this the weather.
Step 2: Preparation
Take the Mason Jar and remove the lid, setting the jar aside for the time being.
Some Mason jars come pre prepared with hole in the centre of the lid and a straw and this will make the preparation a little easier.
If this is not the case then a hole will have to be drilled in the centre of the lid.
The hole in the lid should be slightly larger than the straw to accommodate a grommet and once the straw is fitted in the grommet it should form a air tight seal when the lid is screwed onto the jar.
The straw should be a tight fit and not too easy to slide into the grommet, if it slides in too easily air will escape and the Barometer will not work.
If the straw is too loose in the grommet get a smaller bore grommet, or a wider straw.
Additionally, silicone seal can be applied around the grommet and straw to seal any gaps but only after the height of the straw has been adjusted so that its bottom is one 1/4 of the height of the jar from the bottom.
A thin line of Silicone seal may also be required around the rim of the jar to aid sealing or PTFE tape can be wrapped around the the rim too.
If using Silicone seal ensure it is fully cured before further assembly.
Step 3: Testing
Once the assembly is complete the jar should be tested to ensure there are no leaks around the seals for either water or air.
Simple tests.
1:Dry test.
With the lid and straw assembly firmly in place, suck on the straw after some initial removal of air there should be resistance to any further air removal unless there are any gaps.
Any gaps should be sealed with further PTFE tape, silicone sealer or a gasket. 33