Ideas and Resources for Teaching Astrophysics
Teaching Astrophysics is hard!
How old is the solar system? What is a neutron star? How big is the universe? There’s water on Mars isn’t there? I heard about it coming out of one of Saturn’s moons! Is the universe’s expansion accelerating? How do you know the mass of a star? And how do you know what elements they’re made up from?
The area of astronomy and astrophysics fills so many students with joy as their imaginations run wild, and the questions come pouring out like creme eggs in supermarkets immediately after Christmas. There are so many questions, big and small, many of which are particularly philosophical in nature. Astronomy and astrophysics are such diverse and, quite simply, enormous areas of physics.
Getting good at physics
Much like anything else, being ‘really good’ at physics has for the most part been a result of studying it for so long – throughout school and then intensely at university. Certainly for me, the depth of my understanding and connecting of some of the dots came through teaching it and refining my explanations and understanding as I gained more teaching experience and had to answer the many brilliant questions from my students (that’s another topic for another day). While most physics teachers would consider themselves relatively expert when it comes to mechanics, thermodynamics, electromagnetism, optics, atomic, nuclear and quantum physics, there are few who would fit the ‘expert at astrophysics’ bill. Why would we? We should be confident with the fundamental components of physics that are compulsory and mostly uniform across physics degrees, but astrophysics isn’t one of those.
There are few other examples like it in physics teaching, and it makes this topic area one of the aspects of physics that is a bit more daunting to teach by many. Though that said, there are undoubtedly many examples in other fields of study, like some A Level neuroscience topics in biology or whole realms of history and texts in English where there are significant topics that some teachers would have relatively little experience of but then would have to teach them. I think that the main difference between teaching those is that they generally form larger aspects of the course, so the teacher-working-hard-to-learn to topic-length ratio is quite low for them and high for astrophysics topics. Do science teachers find themselves in a slightly trickier position in terms of being expected to know everything, too?
Teaching astronomy and astrophysics well
As with any topic that you may not have taught before or have become unfamiliar with, you would typically do some research and studying. I know if I was teaching a part of the A Level specification that was new, I would spend time reading some books on it, searching the internet and looking at how exam boards frame their questions in past papers. Then with each sequence of lessons I prepared, I would go to town on making sure I had a real grasp on it. The same approach is perfectly possible and sensible with astrophysics: certainly for GCSE and A Level the examinable content in this area is distinct and clear.
While not wanting to dampen the enthusiasm of the littler ones, I would suggest that making the content for those pre-GCSE years also distinct and clear. Too much open-endedness can be tricky to manage if you do not feel expert in the topic, and obviously we have plenty of non-specialists that will be teaching the subject. At least as non-specialist teachers of Year 7 Cells, there are unlikely to be questions that will stump you! Pick some really great topics that get students thinking and imagining, and where you can make the links to some solid physics. The obvious is the effects of the relative motions of the earth, moon and sun, but you can bring in popular astronomy like constellations and the night sky and link that nicely to intensity by looking at the relative brightnesses and distances of the stars.
Planning and resourcing
Astrophysics relies a lot on understanding scale, and visualising motions of objects in 3D. It is key that you resource well, using simulations and giving students an opportunity to really ‘see’ what is happening. My favourite go-to is the University of Nebraska-Lincoln site that comes with almost any simulation you would ever need, and they actually look good and behave really slickly. The link here gives you their full list of simulations, but they also have some worksheets and lesson ideas. Programs like Stellarium are useful too (and free); this will show you the night sky as it currently is and you can move time forwards and back to show the movement of the different objects along with tonnes of delicious data. There are also the Scales of the Universe applets and videos – with many variations – that give students insight into just how big things are out there. Most of this information can remain overwhelming, so it is important to give some closer to home examples to help visualise what are quite unfathomably large numbers: the toilet paper model of the solar system is a great example to start with — the distinction between the rocky planets and the gas giants amazes me every time.
I have given the impression in some instances in this article that because of the size of the topic that it is worth narrowing down what students (and you) should broach. That’s not quite the point I want to make; we should all strive to be better at our subjects and to develop our subject knowledge. If you feel great about the other areas of physics, then maybe it is time to give this your love. There is so much physics within: take primordial nucleosynthesis, where we had fusion of heavier elements all throughout the universe when it was smaller and hotter, and the Pauli exclusion principle ensuring not-too-heavy dead stars avoid collapse. It is worth spending some time having an intellectual play with it, and the more you use it and teach about it the more it will stick and remain familiar to you and will enrich the quality of the student experience.
There are plenty of popular science books out there that are worth a nosey, such as Big Bang by Simon Singh, but you could also spend a bit of time looking at the GCSE Astronomy books such as the textbook by Nigel Marshall and another written by Sir Patrick Moore and Chris Lintott that is quite meaty. The GCSE Astronomy course is a bit of a popular astronomy feast and some key pieces of astronomy knowledge that really will help in tackling student questions and the space.fm website is a superb accompaniment. It is also worth dipping in and out of the series Cosmos by Carl Sagan (as a TV show or as a series of books); his way with words is an absolute masterclass in illustrating the beauty of physics and, quite frankly, of life itself. It was Sagan that said “Imagination will often carry us to worlds that never were. But without it we go nowhere.”