Blog Archives

Two Minutes of Thermodynamics: Heat Versus Temperature

Sometimes a simple drawing or animation is all that it takes to understand a previously confusing idea. A good illustration of this principle is the following video by Henry Reich which does a good job of explaining the difference between heat and temperature. These two concepts are clearly related but students often erroneously equate them, especially when they first start thinking about them in science class.

A similar, but much older animation from the Eureka! Science series also addresses this thermodynamics issue, but from a slightly different perspective. If you have five minutes to spare, you won’t regret getting a better grasp of this fundamental area of physics.

A Collection of Natural Science Demonstrations from Harvard

Science often feels like a magic show and that aspect makes it particularly appealing to science education. Great communicators of science like Walter Lewin can enchant any audience by turning ordinary physical phenomena into captivating demonstrations that violate intuition and tickle imaginations. In this tradition, Harvard University has created a collection of science demonstrations and simulations covering chemistry, physics, and astronomy. Some of these demonstrations are hard to replicate at home or even in a regular school classroom because of the complex equipment requirements, which is why putting them online is so beneficial. Below is an example of one of the demonstrations that features Chladni plates. More videos are available on the Harvard Natural Sciences Demonstrations Youtube channel.

The Seasons Simply Explained

The fact that certain months are hot and others are cold is so deeply ingrained in our brains that we take it for granted. Fortunately, it doesn’t take advanced science to explain the basics behind this phenomenon. In the “Reasons for Seasons” animation below, Rebecca Kaplan talks about the science of seasons as if she is reading a fairy tale, not giving a serious lecture. This makes for wonderful bedtime learning even if you’re already a serious adult.

Stop Mindlessly Memorizing the Order of Operations

Breaking news: the order of operations that elementary schools teach students is not a fundamental law of nature but a convention to make our lives easier. Unfortunately, many students add PEMDAS (as the order of operations is commonly called in the US) to the list of mystical yet unquestionable truths to be memorized and feared. Everyone’s life might be a bit easier if we realized that mathematical expressions are written in a special mathematical language, and that like any language it has its own rules. The English language, for example, has spelling rules that dictate how to spell the word “bite” in the sense of eating and the word “byte” in the sense of data stored in a computer. If it wasn’t for those rules, there would be a great deal more confusion, and different people would read the same sentence in multiple ways. The same is true in mathematics. The notation and rules that we learn in school have developed over centuries to make reading and writing mathematical expressions an unambiguous activity. In the short video below, Henry Reich explores the conventions we use today and reminds us that thinking deeply about even the most basic ideas is more important than memorizing them. If you’re interested in the history of modern mathematical notation Ask Dr. Math has a bit more information.

Dimensions: A Beautiful Excursion Through Geography, Geometry, and Topology

Unfortunately, some of the most beautiful mathematics is hidden from most people because it is so difficult to visualize. A good explanation has limited reach when the discussion at hand is about geometry, especially when it spans more than two dimensions. We may have an abundance of technology to help illustrate the subject, but someone still needs to spend an enormous of time and energy creating the kind of visualizations that are mathematically accurate, yet breathtaking. Fortunately, a group of French engineers, mathematicians, and education enthusiasts have done some of this hard work and produced Dimensions, an incredible nine part animated film that is nothing short of a visual feast featuring some of the most important and beautiful ancient and modern mathematics

The first chapters of the film introduce geography and the geometry of the sphere. Later chapters extend our intuition about two and three dimensions to four dimensions. The final chapters are more advanced but present a fairly elementary treatment of complex numbers and some topology. Every new idea is presented by an important mathematical personality, putting the whole narrative into a historical context. Although you can watch all nine chapters in one sitting, they are not all connected and it might be easier to watch them separately. The film website has a useful guide to help you choose what to watch, and we can’t recommend watching it enough.

Lively Chemistry Crash Course for Those in a Hurry

Although chemical experiments can yield exciting results, the theoretical part of chemistry may appear overly dry to students who are not already interested in it. Those who are studying the subject and need to review it may be overwhelmed by the sheer volume of details that they need to memorize. In both of these cases, it is helpful to have a highly condensed and lively summary of the key concepts. That is exactly what Hank Green accomplishes in his video series, Chemistry Crash Course. The videos in this series are short and entertaining, but they still highlight fundamental concepts. You can think of the collection as an extended trailer for the much broader and deeper subject or as a fun way to review for a chemistry test. The videos do not replace a textbook or a good teacher but they pack enough content into a few minutes that we recommend pausing them to process all of the information. If you have encountered any chemistry at all, these videos will be a bit more useful than if you have never heard about the existence of atoms.

The Theoretical Minimum: An Introduction to Modern Physics for the Curious Amateur

photo of Susskind

After Walter Lewin wows you with his theater of physics and you become intrigued by the possibility of parallel universes, you may be interested in some of the details behind modern physics. Unfortunately, at that point, you will most likely run into a serious roadblock. Contemporary theoretical physics is steeped in advanced theoretical mathematics, and most textbooks are geared towards future researchers, not intellectually curious individuals with limited backgrounds in either subject.

Luckily, Leonard Susskind, a Stanford Physicist and one of the fathers of string theory, comes to the rescue with The Theoretical Minimum, his unique series of courses on modern physics. The outstanding feature of Susskind’s lectures is that they do not shy away from mathematical derivations; the concepts are introduced in a completely rigorous way, yet they are made accessible to people who have never studied much math or science beyond advanced high school courses. In effect, these lectures offer both a physics and mathematics education for the price of one (figuratively speaking — the courses are free). Susskind develops the material from first principles and introduces all of the math that the physics requires. His target audience is adult continuous learners who want more detail than can be found in popular lectures, but bright high school students will benefit from seeing what life as a physics major entails. It doesn’t look too scary at all.

Jetpacks, Rocket Science, and Basic Physics for Beginners

Rocket science is usually a term associated with something too complicated for mere mortals to comprehend. In reality, the basic principles are fairly simple and involve basic middle school or high school physics. In this video, Derek Muller illustrates Newton’s laws of physics as they apply to rockets and jetpacks and mentions a few other interesting facts along the way. This is an attention-grabbing introduction to the foundations of classical mechanics and as usual with such videos, motivates a further more detail-focused exploration of the subject.

A Quick Look at the Biochemistry and History of Modern Frozen Food

Most of us know that freezing food prevents it from spoiling, but the fact that quick freezing is better than slow freezing is a more subtle point that not everyone may know. As always, Henry Reich delivers a to the point video that addresses this issue and illustrates the science behind modern frozen food. As usual in such videos, some details need to be skipped, but there are enough scientific nuggets here (if you pause it) for further exploration. Even if you don’t take the time to learn about the Arrhenius equation, you will be much more appreciative of modern refrigeration.

How Much Money Is There on Earth? An Entertaining Introduction to the Monetary System

How much money exists on Earth may sound like a silly question, but answering it leads to several important concepts underlying the modern economy. Michael Stevens, in his usual engaging style, answers the question and turns a normally dry subject into an exciting one. His video discusses the creation of money, how it acquires it’s value, and even touches upon some esoteric topics like the dirtiness of physical currency. If you’re an expert on the topic, there may not be many revelations here, but if you’re new to the subject of economics, this is a fun place to start.