This web-based lesson from PSU instructor Christopher Palma provides very straightforward explanations that define and illustrate blackbody and blackbody radiation. If students are struggling with Part 1 of the lecture tutorial accompanying this DigiKit, this is the resource for them. Dr. Palma explains what happens when the blackbody absorbs electromagnetic energy (it heats up and then emits its own radiation). The tutorial will help students with four concepts: 1) Although blackbody spectra are continuous, the peak occurs at a specific wavelength depending on the temperature, 2) The amount of radiation emitted at each wavelength depends only on the object's temperature and no other property; 3) The Stefan-Boltzmann Law relates energy intensity and temperature, and 4) Wien's Law lets us calculate luminosity (energy per unit time) by mathematically relating the radius of the sphere, its temperature, and its peak wavelength.

website

Don't underestimate this resource from ESA. It takes a simple tutorial of blackbody radiation and extends it to explore specifically how astronomers use Wien's Displacement Law to infer the temperature of stars and other cosmic objects at great distance from Earth by simply measuring the "colour of their light". It concludes with a discussion that in certain conditions (i.e., temperatures over 10,000,000K or within very strong magnetic fields), the relations described by Planck and Wien no longer hold true. Scientists call this non-thermal radiation. Upper division students should be aware of it.

website

Here's another free-access tutorial from Penn State's Christopher Parma. It could be a great refresher for students who need to brush up on the components that determine whether a planet may fall within a habitable zone. Key takeaways: 1) The host star must be able to survive long enough for its planets to develop life, and 2) The planets must exist within a certain optimal distance from their stars so that the planets (or their moons) could potentially have liquid water on the surface. The information is presented with excellent clarity.

website

This straightforward tutorial from Princeton's PPPL is appropriate for both lower and upper division. We especially like the 3-minute video explaining the fusion reaction. This resource relates well to Question 3B of the Lecture Tutorial in this DigiKit, which explores the hydrogen fusion sequence on stars like our Sun.

website

This tutorial does a very nice job with explaining what blackbody radiation is, tips for "taking care" with the units in calculation, and exploring how the Stefan Boltzmann Constant is used to calculate total power density. Why we like it: It has a very responsive/intuitive user-controlled graph of spectral intensity vs. wavelength and it is appropriate for upper division courses. Easy to visualize the big picture.

website

This section of the Hypertextbook provides a comprehensive list of symbols used in classical mechanics, astronomy, thermal physics, waves/optics, space & time, electricity & magnetism, and modern physics. The tables are organized by symbol, quantity, and SI unit. Easy to use and read.

website