Psionics Vs Magic Vs Real World Physics

[Vvashjr]

I've been trying to craft as "realistic" battles as much as possible between my protagonists and antagonists, incorporating as much real life physics/chemistry when possible. However I am very stumped by the concept of shields.

Example in theory, my psychic is blocking an earth mage with his telekinesis. This is simply as earth is tangible and material. But what about fire? How do you "block" fire? And more importantly how do you block heat? Is it possible to have telekinesis shield against fire? Or air/wind?

Or what about a magic shield that deflects spells like lightning bolt, fire bolt? Can magical shields deflect, say a wind gust?

 

[CupofJoe]

A fire has substance to it as well. A solid barrier of the right material will block it, the same goes for Air/Wind. They have a mass and a substance to them. Far more fluid maybe, but it is there.
Traditional fires need oxygen to work. Starve them of that and they die. Magical fires? You make the rules.
I like the limitation that Gandalf has that there has to be something to burn... "I can't burn snow..."
Add a bit of Handwavium and you've got a thing that works but has limits.
If you want to block heat, how about removing energy to make things cold?
If a magically-cast Lightning Bolt is governed by much the same physics of a Natual Lightning strike, then ground it. Give it an easier route to Earth than the target... a fine mesh/net of wire [gold, copper, silver] that shoots out like a cloud and flashes brightly as it melts away as the bolt strikes and is earthed.
With "realistic" in quotes, I think you have your answer. Write it, make it so and obey the rules you set up and the reader will probably accept what you say at face value. I don't think many people read Harry Potter and think -
How does "Oculus Reparo" really work?
How does the spell "know" what the fixed glasses should look like?
Are different spells needed if I break sunglasses or a telescope?
[Or maybe they do and I've just not met any of them]
If you are looking for hard real-world laws, then I expect there are a lot of theoretical Physicists and neuro-Psychologists that would love to see the answers too...

 

[Yora]

Heat travels by three means. Radiation, conduction, and convection. Radiation is simply light, and normal flames don't emit very much of it. We really only experience that to a significant degree in sunlight, which is all radiation.
Conduction is heat spreading out evenly through a material. Like when you heat the bottom of a pot and the heat spreads through the sides of the handles. Air is actually really bad at conducting heat, which is why the air between pieces of clothing, within fur, or inside styrofoam is really good at keeping heat from escaping. The big one with fire is convection, which is heat from the fire heating up air, which then moves away from the fire, primarily up, because of the increased pressure.
If you want to block the heat from a fire, you have to prevent the hot air from reaching you. Pushing cooler air against the hot air from a fire should be quite effective, and it also counteracts conduction.

 

[Vvashjr]

Heat travels by three means. Radiation, conduction, and convection. Radiation is simply light, and normal flames don't emit very much of it. We really only experience that to a significant degree in sunlight, which is all radiation.
Conduction is heat spreading out evenly through a material. Like when you heat the bottom of a pot and the heat spreads through the sides of the handles. Air is actually really bad at conducting heat, which is why the air between pieces of clothing, within fur, or inside styrofoam is really good at keeping heat from escaping. The big one with fire is convection, which is heat from the fire heating up air, which then moves away from the fire, primarily up, because of the increased pressure.
If you want to block the heat from a fire, you have to prevent the hot air from reaching you. Pushing cooler air against the hot air from a fire should be quite effective, and it also counteracts conduction.

So in theory you need to telekinetically push at the air to block the fire? I see... fascinating.

Also using this theory, a fire shield can "block" a bolt of lightning then, using the same principles to diffuse the heat right?

 

[Yora]

Lightning is an electrical current. You have a higher concentration of electrons in one point than the other and the electrons move to spread out evenly. When the electrons are moving through any kind of matter, it heats up. In the case of air hot enough to glow white hot for a short moment. The speed of lightning is insanely fast, there is no way to make the air move in the opposite direction at an even faster speed. I think fire shouldn't have any effect on it at all.

The way to deflect lightning is to give the stream of electrons an easier path to leave the point at which they are concentrated. In electrical engineering, the prefered path is always into the ground, where it can spread out across the whole world and dissipate harmlessly. In fact, it would be really difficult to shot lightning at anything but the ground, except when the point of origin is high above the ground and something like trees or roofs are closer.

Assuming you could shot lightning directly at a target, any magic shield to deflect it would have to be raised before the lightning is actually released. It goes from the origin to the target almost instantly. You have to raise the shield while you already see the attacker charging up. One way that might possibly work to deflect it could be to condense the water vapor in the air into a sheet of water that touches the ground. When the lightning hits it, the electrons would follow the water as an easier path to the ground than going through the target. It would of course heat up and be instantly vaporized again. You'd have an explosion, but the thunder from the lightning would already be loud. Oh yeah, when you shoot lightning you always also get thunder. Not as big as in a thunder storm, but it will be a bang.