Physics

The Physics Philes, lesson 123: Conduction, Convection, Radiation, Oh My!

The Physics Philes, lesson 123: Conduction, Convection, Radiation, Oh My!

You know, we’ve been talking a lot lately about energy transfer, aka heat. But we haven’t talked much about how that happens. Let’s fix that now. There are three ways heat can move from one place to another: conduction, convection, and radiation. First, let’s start with conduction. Say you heat one end of a metal rod. Soon, the cold part you are holding will start to heat u... »

The Physics Philes, lesson 122: Heat of the Sublime

The Physics Philes, lesson 122: Heat of the Sublime

WE are elbow deep in heat. We’ve been talking about what heat is and quantities of heat or how heat is measured. But we haven’t talked much about what the addition or subtraction of heat from a system actually means. How does heat effect different materials? The addition or subtraction of heat can obvious lead to a change in temperature. It can also lead to something called a phase cha... »

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... »

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