If you saw my previous post, you know that I am using the Big History Project as our core curriculum this year and that we are currently working our way through Unit 2: The Big Bang. In this post I’ll discuss sections 2.1 – 2.3 and how I adapted them for my elementary age children (4th grader, almost 2nd grader and preschooler).
2.1 How Did Our Understanding of the Universe Change?
Section 2.1 is a pretty thorough introduction to the early astronomers that shaped the way we view the universe today. I summarized the BHP biographies of Claudius Ptolemy, Nicolaus Copernicus, Galileo Galilei, Isaac Newton, Henrietta Leavitt and Edwin Hubble for my kids and found a number of age-appropriate resources, including biographies on Kids Discover online and videos on YouTube. We dove into the ideas of these early astronomers and physicists in depth, beginning with Nicolaus Copernicus.
Copernicus was the first astronomer to deduce that celestial bodies, including Earth, revolve around the sun. This was contrary to the commonly held belief at the time, proposed over 1,400 years earlier by Ptolemy, that the Earth was the center of the universe. It wasn’t until Galileo came along and actually observed the movement of celestial bodies through the “heavens” that Copernicus’ heliocentric theory was accepted as fact.
Activity – Astronomer Biographies
The first activity I had my kids do was to begin scientist biography notebooks. They each chose two astronomers to study and make biography pages for. The pages included relevant artwork and illustrations, important facts, and cut-and-pasted summaries we found online. (My favorite online resource for astronomer biographies is Mr.Cain’s Big History Project Website. Mr.Cain has already done the work of adapting BHP to his 6th grade students, so his summaries are much more succinct than those on the BHP website. I supplemented these with articles I found on Kids Discover Online.)
I won’t summarize the other astronomer’s lives or discoveries here – I just want to give you an idea of what we did with this section of the program.
There is an emphasis in BHP on how human knowledge evolves and on why people change their minds. I personally don’t feel a need to emphasize the analysis of human thought processes with my kids as much as I like to focus on the actual events / experiments / observations that lead people to adjust inaccurate theories, so we had a quick discussion about evidence-based knowledge (how a person can make a claim about how something works and then find evidence to support that claim) but didn’t linger. I wanted to talk about the universe!
2.2 What Are Disciplines?
Physics, cosmology, astrophysics, chemistry, biology, anthropology and history are some of the disciplines introduced in BHP and touched upon in this section. I think it’s important for kids to become familiar with various disciplines and to be able to answer the question of who studies what. I personally was a teenager before I learned that engineers are not just people who drive trains (I am from a family who loves trains and have a brother who worked on them, so it didn’t occur to me until college that the word “engineer” might refer to something else!), and I am trying to avoid that type of knowledge gap with my own children. I love talking about who does what in the world.
As a side note, my three-year old LOVES this book:
She has an expert level understanding of which Disney characters excel at which jobs, and this hopefully will translate into an understanding of who works what type of job in the real world someday!
Activity – The Magic School Bus Science Explosion Game
This game teaches kids about the various disciplines of science in a very engaging, straightforward way. It includes two game boards and an exploding volcano … definitely worth having around for moments like this, when you are trying to explain the multitude of scientific disciplines to your young ones. I pulled it out as a review while we made our way through unit 2.2.
This can be found on Amazon if you are interested in adding it to your toolbox 🙂
Are We Alone?
Now we get to my favorite part: almost hidden in section 2.2 is a video with the title, Are We Alone? Whether or not life exists in the universe is, in my mind, the ultimate astrophysics question. I chose to delve deeply into this topic with my kids (even though it is not particularly emphasized by BHP) because it leads to SO many interesting inquiries. I just could not leave it alone! My kids and I discussed ideas like the following:
- Would alien life forms necessarily have features similar to ours, such as the ability to use oxygen as a fuel source?
- What might their sense ranges be like? (What range of electromagnetic radiation might they detect, what range of sound waves, etc.)
- Would they necessarily have to be carbon-based?
- Would they necessarily have to be 3-dimensional?
- Do the four fundamental forces govern the entire universe, or might there be other forces that physicists haven’t discovered yet? If there are other forces, might there be ways that aliens could travel / communicate / etc. that we simply can’t understand?
And on and on. Although I did get my B.S. in physics years ago, I am pretty sure I missed my calling as an astrophysicist … I could ask questions like this ad nauseam!
Activity #1 – Creating an Alien World
I asked each of my older kids to invent an alien world. They had two main questions to answer: what was their world / planet composed of, and how did their invented alien life form function in this environment?
We have already discussed form and function quite a bit given my 4th grader’s interest in zoology, so we dove straight in to brainstorming how an alien’s form, or body, would evolve so that it could function well in it’s particular environment.
We have done this mind-experiment before, but my kids enthusiastically did it again. Here is a picture of my daughter’s invented planet, Jetspray:
As you can see from her illustration, Jetspray is made completely of water and has two suns, Shyndyke and Glacier. Jetspray’s water moves in constant eddies (she had just learned quite a bit about eddies in a science class at OMSI), pulled by the gravitational forces of Jetsprays suns.
In the upper left-hand corner you can see her aliens – the Hoyak-hoy. They have scales for skin, webbed feet and hands, gills in lieu of a nose, and sea grass for hair. In the lower right-hand corner she has illustrations of the three main types of alien animals that live on Jetspray, two of which are kept by the Hoyak-hoy as pets and another which is raised for meat. They are respectively called Bunnashplooshes, Kitkiats, and Shaw-Shawns. The Kitkiats are fascinating – they have an external digestion bag that hangs off of their stomachs. All three species are equipped with fins to swim on their watery planet.
This exercise definitely stretches the brain – it helps students realize that the limits of human function are very particular to us as a species. Alien life forms (which certainly exist, if you do the math) will have their own unique limitations and sensory ranges … ranges which we might not be prepared to understand with our current knowledge of physics and may not even be able to detect.
Activity #2 – Exploring Alternate Dimensions
Which brings me to our exploration of alternate dimensions.
We tend to take it for granted that we live in a three-spacial-dimensional world. The entire universe, as far as we can tell, is also three-dimensional … with a fourth dimension of time thrown in. But what if, like many physicists believe, there are additional dimensions that we just can’t observe? And what if aliens of some type exist within these alternate dimensions? How can we even think about this type of thing with our limited, three-dimensional brains?
I explained to my kids the concept behind the book Flatland: A Romance of Many Dimensions by Edwin Abbott Abbott. I have actually never read the book, but the idea behind it goes like this:
Imagine that you live in a two-dimensional world. Everything is flat. You yourself are a flat shape, such as a square or a triangle. One day, a cube shows up in Flatland. Of course, you don’t know that it is a cube because that would require you to be able to perceive in three-dimensions, which you inherently can’t do. All you can see is one of its faces (because it happens to be looking directly at you with one of it’s square sides) so you believe that you have just met a fellow square.
Everything is going along great – you seem to have made a new friend – until suddenly the cube turns.
It no longer looks like a square.
Perhaps one of its vertices is facing you now and it looks like a diamond, or perhaps it’s tilted at some unusual angle and you see some oblong-ish quadrilateral. At any rate, this square is not really a square.
You are perceiving only two dimensions of it’s three dimensional shape … and this is all you will ever be able to perceive, given the limits of your senses and your inescapable two-dimensional-ness.
Now, the obvious conclusion to draw from this thought experiment is what if there are dimensions in our universe that we cannot perceive because we are only three-dimensional beings? What if all we can see of these dimensions are the “shapes” or “shadows” they make in our world? And if life forms exist in these alternate dimensions, will we ever be able to detect them, interact with them, or communicate with them?
I had my kids draw multiple two-dimensional images of three-dimensional shapes in order to visualize this concept:
You can see how the 2D shadow a 3D shape makes provides limited information about the characteristics of the shape itself, but provides compelling reason to believe that the shadow exists independently of the object creating it. It is also fascinating to see how many different 2D shapes can be made by each 3D shape … alternate dimensions, if they exist, might look like anything in our world!
2.3 Ways of Knowing: The Expanding Universe
And finally, the last topic we covered in Unit 2 was primarily about Edwin Hubble. Without his revelation that light from nearby galaxies is not only speeding away from us in all directions but is also accelerating as it does so (and perhaps even more importantly, that this means the very fabric of space-time – rather than just the objects sitting around in space – is accelerating outwards in all directions) we would have a very different understanding of the universe.
He was able to determine that light waves are red-shifted everywhere you look in space – they appear to be longer (stretched by the Doppler effect) than you would find if space-time and everything in it were moving away from us at a steady velocity.
A quick refresher: the Doppler effect has to do with how waves stretch and compress as they accelerate past an observer. The classic example is an ambulance, sirens on, racing past you as you stand on a street corner. As the ambulance approaches, it is sending sound waves out in concentric circles around itself. Yet as it races forward, the waves in front of the ambulance begin to pile up, essentially compressing, and adding up in such a way as to create a series of shorter wavelength sound waves. Your ears perceive this as a high-pitched sound. As the ambulance passes and accelerates away from you, the opposite happens – the concentric circles of sound waves spread further and further apart, shifting the sound towards longer wavelengths. The sound you hear becomes deeper.
At any rate, Hubble figured that the fabric of space-time is expanding in all directions at once by studying light from neighboring galaxies and finding it to be consistently red-shifted everywhere he looked. He then plotted the linear relationship between the velocities of these galaxies and their distances from Earth, discovering Hubble’s constant.
Activity – Graphing Linear Relationships
I decided that, for my kids, the take-home messages from this section should be (1) an understanding of linear relationships; (2) a basic understanding of Edwin Hubble’s huge contributions to astronomy; and (3) an introduction to the concept of red-shifting.
The latter two points were made with our reading and the BHP videos we watched, so we got out graphing paper, rulers and pencils and set to work on number (1), finding linear relationships to graph.
We started with the kids’ heights versus time. This relationship is not really linear, but the data points are easy to measure and since we were only graphing four kids it kind of looked linear when we were done. I let them know that with a larger data set it would look much more curved, but they could at least see how, over time, the variable of height changes.
Next, we decided to measure the height of our budding amaryllis bulbs verses time. My daughter collected measurements every twelve hours for about a week and then plotted them. Surprisingly, the amaryllis grew almost exactly a half-inch per day. This was much more linear than I expected and the kids definitely picked up on the concept.
And that pretty much concludes our study of Unit 2. We watched a great many of the BHP videos, some multiple times, and played a ton of space games as well. I will include pictures of our various “space stations” in my next post on Unit 3: Stars & Elements!