This week, the middle-schoolers I work with had a science test. The test covered a space-science unit which touched mainly on the Solar System, the Sun, the Moon, and the concept of scaling – i.e., representing sizes and distances at a different scale. The kids were also challenged to make ample use of scientific notation in their answers: i.e., representing “1,000,000,000” as 1×10^9.
I started observing this class only a few weeks ago, and have only been in the class effectively once a week during that time. I’ve observed my master-teacher’s science instruction, which included a lab on the orbital mechanics and phases of the moon which I thought was engaging and clear – students got their hands on flashlights, model moons, and small globes, and got to experiment of different “Earth-Moon-Sun” configurations to see how the position of the moon in its orbit affected how it would be seen by observers on Earth. There was also a really cool performance task in which students were given a geometric shape on paper and tasked with measuring it, scaling it up by a factor of 2, and then building a wooden replica in the school’s well-equipped shop, painting the replica and then adding it to a tessellating puzzle of all the other student’s pieces.
Tessellation – not my class’s.
Here’s the problem: after all the above engaging, hands-on learning activities, the test showed that a pretty large portion of the students weren’t getting core concepts. The question “Why do we on Earth only ever see one side of the Moon?” yielded results like the following: “Because the Moon doesn’t rotate,” or “Because only one half of the Moon is lighted by the Sun” (which is technically correct, but happens to be the answer to a different question). The clearest indicator to me was the first answer, and those like it – “Because the Moon doesn’t rotate”. (To clarify, only one side of the Moon is ever pointed toward Earth because it completes 1 rotation per month and one orbit per month – thus, its near side is constantly turning toward us as it moves around us.) Clearly this concept wasn’t explained well. Also, I didn’t get a chance to observe my master-teacher’s instruction on scientific notation – but it’s clear from the almost universal arbitrariness of students’ renderings of numbers in this way that this, too, is a concept which will need to be revisited.
My master-teacher was clearly frustrated, and the kids were clearly stressed. Which is all perfectly natural, of course. It left me with a very clear picture of experiences I’m likely to have in the not-too-distant future: seeing what hasn’t sunk in during the course of a unit, and then trying to figure out how to revisit it in a different way. We re-start the unit with a different group of kids in 2 weeks – I’m going to get the opportunity to help teach parts of it, which I’m very excited for – and I’m very curious to see the changes my master-teacher might make to the curriculum, in order to better communicate these concepts and skills to this group of kids.
Just for fun, I’ll throw out one or two ideas of what I might do, had I infinite time and money:
1. Actual astronomical observation of the Moon. Getting to see, as a class, the Moon’s progression through its phases over the course of weeks might make more impact than a lab in a classroom. Too many people simply don’t look up at night, or make an ordered study of astronomy – that’s why it’s easy for average people to get such notions as “the Moon doesn’t rotate”. The difficulty of this, of course, is the fact that we can’t exactly ask kids to come to school after sundown. Or can we – maybe as a once-a-week activity for the course of the unit?
2. Incorporation of truly huge numbers into scientific-notation instruction – for instance, the average distance from Earth to Alpha Centauri (our closest interstellar neighbor at 4.13×10^13 kilometers), or the breadth of the Milky Way galaxy (about 1.04×10^18 kilometers) – and then comparing them to each other. Teach them how to add, subtract, multiply and divide in scientific notation to show kids how useful this notation can be – and to feed into the notions of scale which are the core of this unit, being able to know one quantity in terms of another. I’m not sure the best way to package these ideas, but going through them in a more in-depth and, at the same time, playful fashion might help some students.
Ten Thousand Small Steps 