Heat vs Temperature. How small change in temperature leads to disaster?

Index

• What are heat and temperature?
• Things to learn to understand Heat and Temperature?

            Microscopic and Macroscopic properties.

• How to visualize these properties?

              We can have a system with high temperature and less heat or less temperature and a high amount of heat.

• Understanding with an example.

Heat and Temperature are the most basic things we study in science, specifically in thermodynamics. But there are so many misconceptions about these both quantities.

Let's start with the definition of these quantities-

Heat-  

Heat is the movement of energy or Heat is energy that is transferred into or out of a thermodynamic system by a mechanism involving tiny atomic modes of motion or the corresponding macroscopic qualities. The transfer of energy through thermodynamic work or mass transfer is not included in this descriptive description.

Temperature- 

Temperature is measured as the average kinetic energy of the molecules of a substance. When two objects are at different temperatures, energy is transmitted between them as heat.

Atoms and molecules make up every physical substance that has a quality like a temperature. Even in a solid, the atoms and molecules are always moving. They are continually jiggling and moving, but you can't see it because the movement takes place on such a small scale.

As you probably remember from your study of physics, kinetic energy is a type of energy that is present in moving things and is related to both their mass and the speed at which they are transiting. As a result, when the temperature is expressed as the average kinetic energy per molecule, what is being articulated is the energy involved in this molecular motion.

Things to learn to understand Heat and Temperature-

Macroscopic quantity-  

Quantities in which measurement is made of the entire molecular motion or vibration system. We average the same characteristics across all the molecules in the system.

These physical quantities are often measured by taking averages. They come out as a result of various phenomena in the system. Usually, quantum mechanics don't matter much in these. They usually tend to be constants. 

Microscopic quantity-

The values frequently change over a wide range. For instance, the kinetic energy of elementary particles can range from almost zero to extremely high values in thermal equilibrium (assuming constant temperatures). Quantum mechanics starts to play role in the regime. Individual molecules matter in this regime. As we'll add any property one by one up to the last molecule.

How to visualize these quantities- 

Temperature-

The temperature of the system is the average kinetic energy of its vibrating molecules. So you have a thing that has temperature, you go you look in close all the molecules if they're atoms they're all vibrating. You put a thermometer in there and that vibration gets communicated to the thermometer. The thermometer reads a temperature as the average kinetic energy, the average energy of motion of the vibrating particles. The average means a single particle has no temperature.

So the temperature is a macroscopic thing that you obtain from a liquid, a solid, or a gas, it doesn't matter.

Here's an example. Let's get water, let's stick to celcius, let's say we have room temperature water of 25 to 30 degrees. Some of those water molecules are vibrating very fast others very slowly. Some of them are vibrating fast enough to escape but it's just those only at the boundary of the system. They're at the very top they'll escape and the rest are stuck. 

So now they escape, this is evaporation. You don't have to have boiling water to evaporate the water because the fastest-moving molecules are always escaping.

If you are a low-mass atom or low-mass molecule relative to high-mass molecules your low-mass winds are vibrating even faster on average. You can split them up. The heavy ones are moving slowly and the light ones are moving quickly. The average of all of them that's the temperature.

So we can have a system with high temperature and less heat and less temperature and a high amount of heat.

Heat-

Let's go to that individual vibrating molecule and say how much energy you got. Write down that number. Let's go to the next one, how much energy have you got, write down that number and just keep doing it for every molecule in your system. So the sum of all the kinetic energies of all the vibrating molecules that's how much heat is in the thing. We're adding up all the kinetic energies one by one that the individual molecules do have.

Understand with an example-

So your cup of coffee in the morning at 210 degrees Fahrenheit is hotter than the ocean but the ocean has more heat. Because the ocean has more molecules. That's why your coffee cup is not going to start a hurricane. It doesn't have enough energy in the coffee cup to make that happen and that heat is all the energy in the ocean.

Let's talk about climate change a bit. We have climate change where the world is heating and you can say how much the of the air is heating up? We don't want the air to go up by two degrees Celcius because that could trigger other changes. Well, let's check the ocean, how much did the ocean go? The ocean went up a fourth of a degree or a half a degree and you might say to yourself that's not much.

Do you know how much total energy that is? Huge.

So when you're trying to create the energy budget of a climate system. There's sunlight coming in and it warms the air, is that where all the energy goes? NO.

All the energy there goes into the ocean and can hang out there lurking. So you could reduce, your carbon footprint and reduce the warming of the atmosphere then the ocean says I got heat, I can dump it into the atmosphere and I can keep doing this even after you have corrected your behavior to protect future generations. And the balance( it's actually an imbalance at this moment) is the relationship between the heat that the land retains and the atmosphere and the oceans. The ocean wins every time because of its tremendous heat reservoir. 

So nowadays floods are rising because of this. Because greenhouse gases already have made our atmosphere warmer and heat is just trapped in it. Now even if we plant so many trees it will reduce greenhouse gases like carbon dioxide as trees are made out of it. So ultimately these trees will slow down this environmental change but floods still will rise. We can slow down these changes but can't escape from this completely.

Another example-

Do you know air conditioners work?  It's like it's hot outside and it makes you cool on the inside? Do you ever ask yourself how it accomplishes this?

So what's happening there is, there is heat inside of your room no matter what temperature your room is as long as it's above absolute zero, there is heat there. there's a pump that takes that heat, removes it from your air, and sticks it outside. That's why no matter the temperature outside if you feel the air conditioner it's hotter than the air conditioner. why is it hotter? because it just pulled that heat from your 40-degree room temperature. the room that you're trying to keep cool, it pulled it out and it can reverse that.

So let's reverse it. it's called a reverse heat pump. A reverse heat pump in your winter. You want it to be warmer in your room than outside. Once you switch the heat pump, your air conditioner says, okay, let me take heat from this cold air out there, it's 40-50 degrees I don't care, let's take heat from that cold air and put it in your room and make your room hotter. Even hotter than it would otherwise be compared to the outside. It can do that because there is heat there no matter what the temperature is as long as it's above that as long as it's above absolute zero. it's clever engineering.

Next time you're sipping a cup of coffee and looking out at the ocean, just think to yourself. just know that that ocean has more heat than this hot scalding cup of coffee. you could burn yourself with the coffee but the hurricane won't. it won't matter to the hurricane.

I hope you have learned something new here or found a new perspective on looking at things. Feel free to share it with your friends and family so that they also know how nature works.😊