Lesson: Under Pressure
Lesson: Under Pressure
In this lesson: Under Pressure we are looking at the word "pressure" and all that that implies. English is a lazy language and the word pressure is a prime example. Pressure in english can mean so many things!
Pressure is the amount of force applied perpendicular to the surface of an object per unit area.
Wikipedia
Here at Mezzacello, we use all kinds of pressures for all kinds of purposes. We use water pressure to water gardens and sterilize surfaces and thermal pressure (aka temperature) to boil, freeze, and maintain an ambient pressure, we measure weights and compression, and the water in the atmosphere and underwater. Pressure is a tool everywhere!
Atmosphere
The most important pressure on an urban farm is atmospheric pressure. This is more than temperature. It is how much air, moisture, sunlight, and wind is our atmosphere.
We want optimal atmospheric pressure, not too cold, not too hot. We need rain (and snow) and we most especially want sunlight. Sunlight is its own pressure!
Water
Water is a gas, a liquid, and a solid on this planet everywhere. It is dependent on where and when you are on the planet and the time of the year. But generally, we prefer liquid water, but we have use for gaseous water (vapor and steam) and solid (ice) too.
Water can be pressurized beyond just it's response to the atmosphere! It can be forced mechanically through smaller and smaller holes until it becomes so focused it will cut through steel, or it can rinse of rubber mattes and dirty feet. It's the variability of pressure in water that is important.
Water also has the pressure of weight. In the pond here at Mezzacello the water pressure at the bottom is higher than the pressure at the top. All that water weighs something (1 Liter = 1Kg and 1 gallon = 7lbs).
Water can cause other objects to expand and contract. We count on this aspect of water every day and we rarely think of it. Equipment and materials can be destroyed being exposed to water in the wrong way or at all.
Water has an electrical effects. For example the way electrons flow through wire is VERY similar to the way water flows through a hose. In fact early scientists referred to the pressure in a wire as current (like you find in a river) for just this reason.
Water has magnetic effects too. Water is inherently magnetic at the quantum scale. That's how raindrops, water streams and even rust or oxidation happens.
Water is almost magical in the ways we can use it for work through the application of pressure. Water is not the only pressure game though. There is also light, and air!
Air and Gases
"Air" like what we breathe is NOT a gas. It is a molecular substance composed of many gases and molecules and random materials. Gasses like Oxygen (8%) Argon, and Nitrogen (82%). And molecules like CO2, CO, H2O, and soot. Last bit is random things that make air "dusty".
The air is all of course under pressure in the atmosphere. And because our old friend water is present there is an electromagnetic and weight aspect to air. Lightening and pollution are magnetically derived in air.
Air is also mostly invisible (I say mostly because you can SEE smog and pollution in the air and fog and clouds). Air is also heavy and the air presses more at the surface than in space, just like underwater. This is where we derive barometric pressure (or BAR) which is related to light and water.
Air can be compressed and used to do mechanical work as well. We call it air pressure and it is really important to a farm. Look at the way air in the soil works or air in a tire works, or the way the air in your lungs works.
Light
Our solar furnace produces incredible amounts of light and magnetic quantum effects that we are ENTIRELY reliant upon. All life exists thanks to water, air and light. And light has a pressure as well.
When the light from our star (their name is Sol, by the way) reaches the outer layer of our atmosphere, it creates pressure. then as the light penetrates into the atmosphere it grows in pressure, we call this temperature. Most of our planet is at two very important pressures: bar and temperature.
Bar pressure is the pressure of energized, compressed air and vapor at sea level. That is one bar and that is most of the planet - except mountaintops and ocean depths. then it varies a little up (underwater) and down (up into the sky).
Temperature is generally 21C (70F) as a baseline. Then depending on where the light is penetrating (and more importantly infrared bandwidths) hits it gets up to 45-50C and down to -42C. Ohio, where Mezzacello is on this planet, the temperature varies between -15C and 45C.
Water, Air, Light and Seasons
So pressure is the reason we have seasons on this planet. The globe spins into and out of the sun, day to night, and around the sun (year) and on its axis (seasons). All that motion and its pressure on air, water, and light make seasons. People complain about seasons, but our life on this planet is completely dependent on them.
If you don't want a planet with the "inconvenience" of seasons, consider living on another planet. Mars doesn't tilt - Mars' moons are WAY too small to cause it to wobble like Earths Moon does. So Mars has no seasons and thus it is really COLD (-100C) OR it is WARM (45C) where all life perishes.
Electricity
There is pressure in electricity and it is called Amperage or Amps or Current. The more Amperage you have the more Voltage you must have and then there is the added issue of Heat from Friction. The pressure in electricity is ENTIRELY electromagnetic.
Just like all the other forms of Pressure we have been discussing, we can use the pressure of electricity to do work. When we think about pressure in the flow of electrons, we need to focus on Direct Current or Alternating Current. There is a BIG difference between the two and it is related to pressure.