Physics

The Physics Philes, lesson 121: Mountains Out of Mole Hills

The Physics Philes, lesson 121: Mountains Out of Mole Hills

Is it hot in here? Yes! Because we’re continuing our discussion of heat! Last week we learned about specific heat. We generally measure specific heat as a mass per change in temperature. However, sometimes we might want to use the number of moles of a substance, rather than the substance’s mass. Whoa whoa whoa…mole? Like an animal? No. Don’t be silly. A mole is the number o... »

The Physics Philes, lesson 120: Very Specific Heat

The Physics Philes, lesson 120: Very Specific Heat

Brrrr…it’s cold outside. Frigid, even. There’s a dusting of snow outside my window as I type. One might be forgiven for thinking that there isn’t as much heat outside as there is in the summer. But that’s not quite right, as least in the wonderful world of physics. Temperature and heat are distinct things. Heat is an energy transfer that takes place because of a tempe... »

The Physics Philes, lesson 119: Turn Up the Heat

The Physics Philes, lesson 119: Turn Up the Heat

Wow. It’s been three weeks since I last wrote about physics. Three whole weeks. Life, man. You know how it is. But I have not forgotten. Let me pick up where I left off. Let’s see…*flips through notes*…aha! It’s time to talk about thermal expansion. Thermal expansion is pretty much what it sounds like. When most materials are heated, they expand. We can see this in ev... »

The Physics Philes, lesson 118: Heat, Temperature, and the Zeroth Law of Thermodynamics

The Physics Philes, lesson 118: Heat, Temperature, and the Zeroth Law of Thermodynamics

Most of us have spent our entire lives learning about heat and temperature. We know we have to cook some food to make it safe, or store food in an icebox or refrigerator. We know it hurts to touch things that are too hot or two cold. But these measurements of heat and temperature are subjective and imprecise. That won’t do in physics. We need to figure out a way to talk about heat and temper... »

The Physics Philes, lesson 117: Sonic…BOOOOOOOM

The Physics Philes, lesson 117: Sonic…BOOOOOOOM

Well, well, well…we’re about to wrap up this section on waves. But before we do let’s take a peak at one of the spectacular things sound waves can do, sonic booms. We can use the equations we learned about previously to show why this happens. Think about an airplane moving relative to the air at a speed vs. (It’s just the speed, so it’s always positive.) The motion of... »

The Physics Philes, lesson 116: Relativistic Doppler Shift

The Physics Philes, lesson 116: Relativistic Doppler Shift

I know, I know…I didn’t write anything about physics last week. It hurt me more than it hurt you, I promise. Let’s see. Where did we leave off? Oh yes, Doppler shift. As we found last week, sound waves can be shifted if either the source of the sound or the listener is moving. After our derivation, we found that the frequency, as heard by the listener, can be found by this equati... »

The Physics Philes, lesson 115: The Doppler Shift

The Physics Philes, lesson 115: The Doppler Shift

We’ve been talking, over the last several weeks, about sound and sound waves and how those waves interact with each other. Implicit in those discussions is the assumption that everyone is at rest relative to one another. That’s not always how it works. We know, of course, that we can hear things eve if they are moving. It would be a pretty weird world if we couldn’t. But that doe... »

The Physics Philes, lesson 114: We Got da Beats

The Physics Philes, lesson 114: We Got da Beats

Remember last week we learned all about wave interference. As I mentioned at the end of that post, we stuck to waves that have the same frequency. But that’s not always how things work out in the real world. Something slightly different happens when we have two waves overlap that have slightly different frequencies, and all we have to do is apply some concepts we already know and love. Let&#... »

Page 1 of 13123»