Entries by anorlunda

How to Better Define Information in Physics

When I ask questions about conservation of information I frequently get the reply, “It depends on what you mean by information.”   So, I researched how to better define information.  What I found is almost more interesting than the conservation question.  That sounds like the makings of a fun PF Insight article, so here goes. This […]

3 New Years Tips For Cooling Off Debates

  Civil discussion and debate is critical to Physics Forums. But it is also important in everyday life. When arguments get overheated, people may avoid engaging with friends and family and the relationships could wither and die.  If the only safe topic you can discuss with your friend is weather, your relationship is in danger. […]

The What and Why of Circuit Analysis Assumptions

Probably everyone reading this article already has an education on elementary circuit analysis (CA) and many of us are much more advanced. Typically, the basic course covers both circuit covers simple devices like R, L and C, it mentions electric or magnetic fields, then moves on to Ohm’s Law and CA.. But few such courses […]

Why Study Physics? A Bit Goes a Long Way!

If you don’t plan to become a scientist or an engineer, is there a good reason to study physics?  I say, “Yes,” because knowing just a little bit can be quite rewarding in ordinary life.  For example, I have been enjoying just one little bit of physics for more than 55 years.  I even earned […]

Why Ohm’s Law Is Not a Law

At first I wanted this title to say “Ohm’s law is not a Law.”  But someone else used that phrase in a recent PF thread, and a storm of protest followed.   We are talking about the relationship between Voltage between two points in a circuit and the current between those same two points. ##R=V/I##, or […]

AC Power Analysis: Cyber Resilience

  Power system security is much too big a topic for this article.  But I can squeeze in a few points about vulnerability to cyber attacks.  First, this topic follows naturally from Part 2’s discussion of grid control (remember that flyball governor?).  Second, I feel that’s apropos in an era where the public believes that […]

AC Power Analysis: Network Analysis

  Let me use the terms “power grid” and “network” interchangeably. What is the Power Grid Required to Do? Deliver energy to customers, and thereby earn money so that the utilities can profit. Deliver power wherever and whenever the customers demand it. That implies maintaining the dynamic balance between energy produced, energy lost, and energy […]

AC Power Analysis: System Basics

  Instantaneous Power The formula for power is: ##P=V\cdot I## , power= voltage*current.   We call that, instantaneous power.   Even when ##V##  and ##I##  are changing in time,  ##P=V\cdot I## applies for each instant.  It matters not if the ##V## or ##I## changes are `sinusoidal, what their frequency is, or even if they are aperiodic. ##P=V\cdot I## […]

The Case for Learning Complex Math

Resistance to complex math seems to never die out.  I see it frequently in PF posts.  Often it takes the form of challenges rather than questions.  First challenge: Complex is just a mathematical trick that has nothing to do with the physics.  Second challenge: Everything that complex does can be accomplished by ordinary real numbers.   […]

Exploration into the Physics of Rainbows

For several years, I have been contemplating this beautiful picture by photographer Brian McPhee.  I have a personal interest in the photograph because that boat is my year round home.  I also have a scientific interest in the photograph because of what it teaches me about rainbow physics. The simplest explanation of rainbow physics is […]

What Happens When You Flip the Light Switch?

Few people know what happens when a customer does something like flipping a light switch. The full explanation requires descriptions of topics that span nanosecond to decade-long time scales. Think of it as scales measured with a high speed chronograph, a stopwatch, an hourglass, or by a calendar. At the earliest and briefest instants, pure […]