Students state the conditions for solar and lunar eclipses, distinguish the umbra and penumbra, and explain why eclipses do not occur every month (AC9S7U03, node 3).
Load these into Waypoints Prepare: choose Load URL and paste the copied address, or download the file and import it. In Prepare, the worksheet's Teacher edition shows the answers; the student copy hides them.
Engage and Explore 8 min · Explain 8 min · Evaluate 3 min · Typical adds 3 min, Wider about 2 min
A concept tutorial for introducing or revising the idea; it pairs well with a lamp, a ball and a hoop tilted to show the moon's orbit. Set the width with ?width=minimum, typical (default) or wider.
The node isn't a hinge, but it depends on the moon-phase model (node 2): a student who thinks phases are Earth's shadow will confuse a lunar eclipse with a phase. The 3D step (the tilted orbit) is the hard part; the board shows it in a side view with the tilt and the shadows exaggerated.
Board notes: each step is half a month (29.5-day month). The line where the moon's orbit crosses the plane of Earth's orbit turns relative to the sun once every 346.6 days, so eclipse seasons come a little under six months apart; the board starts so that the first eclipses come in about month 4. Eclipse types use real angle limits (for example, a lunar eclipse is total when the moon is within about 0.4° of the plane). Solar eclipses are seen only from a narrow path or region of Earth. The 2028 total solar eclipse crosses Sydney on 22 July 2028.
Thinking in three dimensions: the tilted orbit means the shadows usually miss. When a student expects an eclipse every month, ask what the side view shows at most new moons.
| What you will see | A question to ask | The fix |
|---|---|---|
| A student says a lunar eclipse is the same as a new moon. | Where is the moon in a lunar eclipse: between us and the sun, or behind the Earth? | Behind the Earth, at full moon: Earth's shadow falls on it. |
| A student thinks the moon's shadow covers the whole Earth in a solar eclipse. | How big is the umbra where it reaches the Earth? | Small: the total eclipse is seen only from a narrow path. |
One possible solution for each task. Other correct programs are fine.
Open task: any program that does what the step asks.
Open task: any program that does what the step asks.
Stretch: Why do lunar eclipses happen at the same 'season' as solar eclipses, about two weeks before or after?
Support: Give side-view outlines of the sun, Earth and moon in a line, to shade the shadows.
For a student who has done the lesson and is still stuck. They paste it into an AI tool your school allows; it asks questions about this lesson's one idea and doesn't give answers. Students see it on the course recap page only through a link ending in ?coach=1: recap with coach prompts.
You are a patient science coach for a Year 7 student in Australia. Help me understand ONE idea only, from the lesson "Why isn't there an eclipse every month?". The idea: Eclipses: solar and lunar: I can explain the conditions required for solar and lunar eclipses and why eclipses do not occur every month. What understanding looks like: - States the conditions required for both solar and lunar eclipses - Correctly distinguishes umbra from penumbra - Explains why eclipses don't occur every month Mistakes students often make here: - A student says a lunar eclipse is the same as a new moon. - A student thinks the moon's shadow covers the whole Earth in a solar eclipse. How to coach me (rules from the Waypoints Kit coach): - Ask me one short question at a time (2 to 4 sentences) and wait for my answer. Never give me the answer before you have heard my thinking, and don't hide the answer inside your question. - Start in Discover: ask me to explain the idea in my own words, or to predict what happens in a simple example. I can switch any time: "teach it back" (you play a beginner and I explain), "spot the flaw" (you show me an answer with one common mistake and I find it), or "check" (I explain, and you tell me what is solid and what to revisit). - If I am stuck or say "just tell me", ask what I think first, then give a small hint or a simpler example. Explain only after I have had a real go. - If I seem to be missing the idea that comes before this one (Moon phases and the lunar cycle), check it quickly, then come back. - Stay in this idea: don't teach later ideas or add extra content. If I ask about something else, say it is for another lesson and bring me back. - After you help, ask me one reflective question, such as how I know my answer is right or what I would check. - Praise my effort and method, not my ability. - You can be wrong: if I rely on something you said, remind me to check it against my notes or the lesson. If you don't know, say so. - Use simple words. - Stop when I can explain the idea in my own words and get one new example right. Then tell me to go back to the lesson "Why isn't there an eclipse every month?".
Why doesn't every full moon give a lunar eclipse?
The moon's orbit is tilted about 5° to Earth's, so at most full moons the moon passes above or below Earth's shadow.
Next: tides (node 5).
In class: a lamp, a ball and a tilted hoop; look up the next eclipses visible from your town.