Jiggling Particles and Hot Stuff...

Everything we study in science generally comes back to the one thing we cannot measure absolutely...energy. Whether we are studying the kinematics of large objects like trains, planes, and automobiles or we are examining the behavior of large groups of nanoscopic particles like atoms and ions we can only measure the change in energy not the total or absolute amount of energy. This idea, in and of itself, occupies and very special singularity in the universe and has incredible ramifications.

In chemistry we study thermodynamics in terms of enthalpy, temperature, entropy, and free energy. When we study reactions we ascertain whether the reaction is exothermic or endothermic, i.e., is the change in enthalpy negative or positive. If it is endothermic then heat is absorbed in the process and heat (enthalpy) is a reactant in the thermo chemical equation. In this case the change in enthalpy is positive. If it is exothermic then heat is emitted into the surroundings and it is a product in the thermo chemical equation. In this case the change in enthalpy is negative.

What does this say about work? An endothermic reaction has work done on it from the surroundings and an exothermic reaction does work on the surroundings. The particles of the surroundings slow down during an endothermic reaction and the particles of the surroundings speed up during an exothermic reaction. It is all about the work...it is all about the particles. As Richard Feynman says so eloquently…particles ‘jiggle’.

Consider a closed piston with a plunger. If you add heat to it you will speed up the particles and they will expand pushing the plunger up and therefore doing work on the surroundings. Consequently if you remove heat from it you will slow the particles down...they will lose kinetic energy...and the volume will decrease as the surroundings do work on the piston. Everything is about work...and heat...and particles (internal energy)...and ‘jiggling’…

The far reaching ramification is that we can not measure the total energy in the universe because we can't seem to stop all the particles from moving...and this includes the subatomic particles. Supposedly absolute zero is defined as the absence of all heat...but, and this is according to Feynman...heat correlates directly with particle motion...however, if we stop all particles from moving it will include the subatomic particles and that would violate Heisenberg's Uncertainty Principle because then we could in fact define the position and momentum of a particle simultaneously...so therefore we are always measuring changes in energy.

So I guess absolute zero could be a singularity just like the speed of light and maybe we will never get there...I say maybe...

The Pale Blue Dot...or a Matter of Perspective

When Voyager turned around and took a picture of earth from the other side of Neptune it started a chain of opinionated rhetoric about our existence and the possibility of extraterrestrial life. Carl Sagan, of course, led the charge and used the image to amplify our insignificance as a species from the perspective of the 'backdrop' of the universe. I am not convinced of our insignificance 'according to Sagan' but I will admit that we do appear small as compared to all of space. If anything this picture tells that Ptolemy's geocentric universe and Copernicus' heliocentric universe are just theories along the way. And we know now that they are not true. Ah, but for the process of scientific inquiry...hypothesize...test...re-hypothesize...etc.

Voyager was an amazing feat of modern engineering but the rules for space travel were established by Johannes Kepler and Isaac Newton during the seventeen century. This fantastic journey has allowed us to become acquainted with our solar system neighbors. It has provided us with vital clues as to the existence of life outside of the earth. And it has brought us even closer to the reality of humans traveling on long term space missions.

I don't agree that we are insignificant because we are small. We are significant by the mere fact that we can send Voyager across our solar system and beyond. We are significant because we can dream and wonder and accomplish our goals. We are significant because we are alive and sentient...and because we can learn.

The scientific and engineering accomplishment of the Voyager program is astounding. The application of Kepler's laws of planetary motion and Newton's law of gravitation is a validation of the scientific process and is an imperative mandate for all of us to ask questions, render hypotheses, and learn from everything we see and do. Remember the scientific process skills.

Electric Fields and Electric Potential

We did a pretty interesting lab where we mapped an electric field in the bottom of a plastic tub. In one direction (horizontal) we measured electric field lines and in the other direction (vertical) we measured equipotential lines. Our readings had a very definite trend and that trend tells a great deal about the nature of an electric field, about the concept of voltage, and about the work and the electric charge.

The electric field lines went from the positive plate to the negative plate as in the figure below. So what is the trend of your voltage readings along your electric field lines?

Now the equipotential lines are also shown in the figure. They are vertical. Can you see a trend in those numbers?

Here's another talking point: what do we mean by voltage? Every reading we took was in volts. What does it mean? What are the units of a volt? Does a volt imply anything about work?

Think about this: if you take an electron and put it next to the negative plate will you have to do a lot of work to keep it there? And what about the same thing for a proton against the positive plate?

Respond to the blog posting, first of all, by responding to the "thought" questions posed above. Along the way make sure you define the following: electric field lines, equipotential lines, and voltage. Make your response at least two large paragraphs and sign only your first name to the blog. Also, remember to respond to one other posting from one of your classmates.

The Answer to all Questions is Work

Everything we study in science generally comes back to the one thing we cannot measure absolutely...energy. Whether we are studying the kinematics of large objects like trains, planes, and automobiles or we are examining the behavior of large groups of nanoscopic particles like atoms and ions we can only measure the change in energy not the total or absolute ammount of energy. This idea, in and of itself, occupies and very special singularity in the universe and has incredible ramifications.

In chemistry we study thermodynamics in terms of enthalpy, temperature, entropy, and free energy. When we study reactions we ascertain whether the reaction is exothermic or endo thermic, i.e., is the change in enthalpy positive or negative. If it is endothermic then heat is absorbed in the process and heat (enthalpy) is a reactant in the thermochemical equation. In this case the change in enthalpy is positive. If it is exothermic then heat is emitted into the surroundings and it is a prodeuct in the thermochemical equation. In this case the change in enthalpy is negative.

What does this say about work? An endothermic reaction has work done on it from the surroundings and an exothermic reaction does work on the surroundings. The particles of the surroundings slow down during an endothermic reaction and the particles of the surroundings speed up during an exothermic reaction. It is all about the work...it is all about the particles.

Consider a closed piston with a plunger. If you add heat to it you will speed up the particles and they will expand pushing the plunger up and therefore doing work on the surroundings. Consequently if you remove heat from it you will slow the particles down...they will loose kinetic energy...and the volume will decrease as the surroundings do work on the piston. Everything is about work...and heat...and particles (internal energy)...

The far reaching ramification is that we can not measure the total energy in the universe because we can't seem to stop all the particles from moving...and this includes the subatomic particles. Supposedly absolute zero is defined as the absence of all heat...but, and this is according to Richard Feynmann...heat correlates directly with particle motion...however, if we stop all particles from moving it will include the subatomic particles and that would violate Heisenberg's Uncertainty Principle because then we could in fact define the position and momentum of a particle simultaneously...so therefore we are always measuring changes in energy.

So I guess absolute zero could be a singularity just like the speed of light and maybe we will never get there...I say maybe...