Scratch

Topics: Programming
Explanation Quality: Good
Medium: Code; Video
Type of Content: Educational

Scratch is a little different from the other websites I've posted about. Created by the MIT Media Lab, it allows you to program your own games and animations without any background knowledge of coding! It does this by taking a small chunk of code (something like "move to this position" or "change the background color") and formatting it as a puzzle piece. You then can connect all the pieces together into a script that does something cool.

This is a look inside a program I created. As you can see, there are multiple scripts (the segments on the far right of the screenshot). In the middle, there are some of the puzzle pieces you can drag over. The screen on the right shows my program.

You can either dive in right away, or watch some video tutorials first. I like this site because it's a good way to start out with programming. There is no syntax to learn, and you can immediately see if your program works. Most new users are in their teens, but anyone can join. I actually first used Scratch way back in middle school. If you have a lot of experience with computers and programming you might not find Scratch interesting (though there are a ton of commands to choose from, there are some limitations). But if you have little/no experience, or are bored and want to make a fun game, this is worthwhile to check out.

What if?

Topics: Anything is fair game
Explanation Quality: Good
Medium: Text
Type of Content: Answers to questions

If you've ever asked yourself a ridiculous hypothetical question, xkcd's what if? is the place for you. Here Rundall Munroe answers reader submitted questions ranging from "How close would you have to be to a supernova to get a lethal dose of neutrino radiation?" (answer: a little more than the distance from the sun to Mars) to "If cows could photosynthesize, how much less food would they need?" (answer: a few handfuls of grain).

 

Although the questions may sound ridiculous, the answers are not. Well, maybe they are, but they're accurate. Munroe researches all of his responses thoroughly. He even cites his sources! I enjoy this site because it's funny and informative. I learn a lot of random facts through reading these. And, each post always includes several illustrations. So if you're wondering "what if?", go check it out!

Better Explained

Topics: Math; Programming
Explanation Quality: Better
Medium: Text; Pictures
Type of Content: Educational

Better Explained is a blog whose motto is "Learn right, not rote." I stumbled across it one day while trying to get a better understanding of the number e. (If you want to know what e is, check out the article on it). My experience with e in school was that it was a number that showed up a lot with exponents and logarithms. No one really explained where it had come from. The article I found on Better Explained really helped me understand. It took the explanation one step at a time, using graphs to approach the idea that e is the base for continuous exponential growth.

The thing I like best about this blog is that it helps you get a sort of intuition. The writing style is friendly. The author, Kalid, uses words and pictures as well as math to help you get a sense of what he is explaining.

From the BetterExplained article on Bayes Theorem

The blog has about 61 articles talking about math, with the topics ranging in complexity from arithmetic to vector calculus. But all of them are readable, no matter what your level is. There is also a section on programming and web development. I haven't looked at this part much (I do want to learn more about computers, but that's a goal for next summer when I have more time). From what I have seen, the explanations look similar to those in the math section. There are also some articles with tips on doing some computer things like working with Ruby on Rails and debugging.

This blog is worth checking out if you have a specific topic you don't understand, or if you're bored and want to see a new way of looking at something.

MinutePhysics

Topics: Physics; Math
Explanation Quality: Better
Medium: Video
Type of Content: Educational

MinutePhysics is a YouTube channel focusing on - you guessed it -physics! All of the videos are time-lapsed drawings (it looks like they are down on a white board) with a voice over. The videos are never very long, usually three minutes or less. Two of my favorites are the video on quantum tunneling and the one on round triangles.

Because the videos are short, watching them is a fun way to learn a bit about a lot of different areas of physics. Last year, when the LHC discovered the Higgs Boson like particle, MinutePhysics made a few videos explaining what the Higgs Boson would do and why it was important. Some of the videos cover common physics misconceptions. Overall, I really like the way he both explains and illustrates his points. It really helps my understanding. And since the explanations and drawings often have a bit of humor, that makes me like them even more.

Basically, if I have nothing to do, I can go check out MinutePhysics and consistently be both entertained and educated. So go check it out!

Rising Heat

Hot and Cold

• blue or green colored ice
• red food coloring
• warm water
• large container

Make blue or green colored ice (see the beginning of Mixing Colors for an explanation). Fill the large container with warm water. Make sure the container is as still as possible (as in, not on a rickety folding table). Try to minimize it's movement throughout this activity. On one side drop in a few ice cubes, on the other side put in a few drops of red food coloring. Now observe.

The red is hot water and the green is cold.

You can talk about a few things with this activity. One is why the food coloring spreads out instead of just staying where you dropped it. This is because the molecules in water are always moving. Their movement knocks around the food coloring molecules and causes them to spread out. You may also notice that the red spreads out faster than the blue. This is partly because the blue starts out trapped in the ice, but also because the molecules in the hot water are moving faster. Heat is energy. If you have more energy, you move around more. The same is true for molecules. So the faster moving warm water molecules knock into the food coloring more than the slower moving cold water molecules, thus spreading the color around faster.

The main point of my explanation when I did this was about the layering of the colors (I had this as part of my weather themed activity set). If you don't disturb the water, eventually the red water will be in the top half of the container, and the blue water will be in the bottom half. This is because the blue food coloring is staying with the cool water, and the red with the warm water. The reason the different temperature waters separate is because of density. Density is mass/volume, or how much stuff there is in a certain amount of space. Hot water is less dense than cool water. My friend had a really good intuitive explanation as to why this is true:

Think of a bunch of kids sitting at a table. Right now that don't have much energy, so they stay where they are. Then you give them a bunch of energy. Now they are probably running all around the room, and only a few are still at the table. The kids represent the molecules in the fluid. The energy you give them is heat. The table is the space we're comparing. In the first case there are a lot of kids at the table, or a lot of stuff in the area, so it is pretty dense. In the second kids, only a few kids are at the table so there is less stuff in the area and the density is lower.

Learn More:
http://www.landa.com/docs/HotWatervsColdWater.pdf
http://www.mansfieldct.org/Schools/MMS/staff/hand/atomsheat.htm
http://phet.colorado.edu/en/simulation/density
 

Scientific American

Topics: Science (Biology, Chemistry, Physics, Linguistics, Computer, etc.); Engineering
Explanation Quality: Best
Medium: Print, Graphics
Type of Content: News

Scientific American is my favorite magazine. I've been subscribed for the past three years. I always get really excited when I see that it has arrived in the mail. Every month the have several feature articles on some new, recent topics. Occasionally, the article is themed and all the featured articles are related. For example, the September 2013 issue is all about food - looking at it from nutritional, ecological, and historical perspectives, among others.

They also have specific columns every month, such as the Science of Health and TechnoFiles. I really enjoy SA because it has a nice variety of articles, and I can learn things in fields that aren't my main interest. I also find it convenient that I can bring a magazine with me to read when I don't have internet.

It is also a very reliable source. I don't need to bring my usual skepticism when reading SA because the writers of the articles are (for the most part) scientists who were involved in the research. 

If you can't subscribe yourself, see if your library does. It is also worth checking out their website as they have some full articles there as well.

EdX

Topics: All (Business, Sciences, Philosophy, Economics, Engineering, History, Law, Humanities, etc.)
Explanation Quality: Best
Medium: Video, Text, Powerpoint, Interactive exercises, Problem Sets
Type of Content: Educational

EdX is a collection of free Massive Open Online Courses (MOOC's). If you've never heard of them, MOOC's are courses (normally college courses) that anyone, anywhere can take as long as they have access to the internet. Carnegie Mellon University's Open Learning Initiative is another example of them. However, there are a few key differences. One is that edX currently offers a total of 50 courses from13 different schools. If a course has already finished running, many still allow you to look through the lectures and notes. Most courses will give you a certificate of mastery upon completion. Overall, these are more like taking a real college course, just online.

A screenshot from my Quantum Mechanics class

I am currently signed up for a class on quantum mechanics from The University of California, Berkeley. It runs for 10 weeks. 8 of those weeks are classes, one is a midterm, and one is a final. Every Saturday the material for the next week is released. This is two video lectures (though each is broken up into smaller segments), a copy of the course notes, and a set of homework problems. If you want credit for the homework, it has to be completed by the next Sunday. You can audit any course and simply watch the videos and read the notes, but if you want a certificate, you need to get at least a certain grade. In my course this is an 80%.

There are several other helpful features. The discussion forum is really helpful if you don't understand something. There are also TA's who occasionally post hints or other useful information. In other courses, there can be interactive labs. For example, some chemistry courses have a molecule editor which allows you to "create" molecules in order to answer questions, or just get a feel for how things work.

So far, I really love this site. If you want to learn a new subject, this is definitely a good place to check out. Not all of the courses are entry level though. Each will state its prerequisites on its main page. For example, my course requires knowledge of linear algebra to complete. But it is still worthwhile to check around, even if you don't have anything in particular you want to learn. You map find something that surprises you.