Total Eclipse: The Solar Eclipse This August Is an Ideal Opportunity to Practice Three-Dimensional Science Learning

[ILLUSTRATION OMITTED] [FIGURE 1 OMITTED] This summer, on August 21, 500 million people across North America will experience one of the most beautiful astronomical phenomena: an eclipse of the Sun. It will be a "must teach" moment, when all students will want to know the "what, when, and why" of the event. In addition, many high school science teachers are likely to be asked about it, not only in their classes, but in discussions with colleagues, family, and community members. Research shows that many high school students--and adults--fail to correctly understand the Earth-Sun-Moon system (Hermann and Lewis 2003). If you are lucky enough to be in the 100-kilometer-wide path of totality, you will see the Moon completely cover the Sun. When only a sliver of sunlight is visible, your surroundings will darken, as if the Sun were setting. Temperatures will drop, and birds will go to roost, thinking that night is coming. Finally, the Sun will be totally covered, and the beautiful solar atmosphere (the corona) will become visible (Figure 1). Totality will last about two minutes for this eclipse, depending on location, and then the Sun will slowly be uncovered. While only those people in the narrow 100-kilometerwide band will see a total eclipse, everyone in the United States (as well as Canada and Mexico) will see at least a partial eclipse (Figure 1), where a "big bite" is taken out of the Sun. Teachers, students, and families will want to enjoy its beauty and will need to be prepared to safely observe the event. More information regarding where and when the eclipse is visible, plus safe viewing strategies, are in the insert in this issue of The Science Teacher. The insert can also be accessed online (see "On the web"). By August, we expect enormous media and public interest in the eclipse and how to observe and understand it. Science teachers can help students and communities prepare. Eclipses are rare and exciting events that generally produce a feeling of cosmic awe and mystery, but people's sense of wonder can be further enhanced by a clear understanding of what causes them. Indeed, the 2017 eclipse provides a great hook to engage students in wanting to know what causes the phases of the Moon (key to understanding eclipses), how and when we get solar and lunar eclipses, and why people travel thousands of miles and spend thousands of dollars to see a total solar eclipse. The eclipse and three-dimensional science learning For educators, the eclipse and its associated ideas provide the perfect opportunity to incorporate three-dimensional learning (3-D learning) into your teaching, as recommended by the Next Generation Science Standards (NGSS Lead States 2013; see box, p. 38), covering science and engineering practices (SEPs), disciplinary core ideas (DCIs), and crosscutting concepts (CCs). The goal of 3-D learning is to interweave the dimensions, so students see them as a connected whole. Not every individual activity lends itself to incorporating all three dimensions. It is only when you look at a sequence of learning experiences that one can identify effective ways to incorporate 3-D learning. Helping students to understand what causes solar eclipses provides an ideal opportunity to connect a number of learning experiences over several weeks. These not only incorporate 3-D learning but also include other essential learning strategies, such as assessing prior student understanding of the subject and assessing the learning that occurs during and after instruction. 3-D learning in action So, how does 3-D learning actually work in the classroom? The following set of learning experiences asks students to demonstrate their current understanding of lunar phases before they learn what causes these phases and then finally gain a full understanding of solar and lunar eclipses. These activities come from our book, Solar Science: Exploring Sunspots, Seasons, Eclipses and More, available from NSTA Press (Schatz and Fraknoi 2016). …