Students explain tides as caused by the moon's gravity, account for two high tides a day, and link spring and neap tides to the moon's position and phase (AC9S7U03, node 5).
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 7 min · Explain 7 min · Evaluate 3 min · Typical adds 1 min, Wider about 2 min
A concept tutorial for introducing or revising the idea; pair it with a real tide table for a coast near you (Bureau of Meteorology tide predictions). Set the width with ?width=minimum, typical (default) or wider.
This node integrates the moon's phases (node 2), the line-ups from eclipses (node 3) and gravity (AC9S7U04). Students who can do each part separately often can't put them together; the board joins the bulges, the moon's position and a month of tides in one view.
Board notes: the bulges are hugely exaggerated, and the far-side bulge is shown without explaining it fully (at Year 7, "the moon pulls the near ocean more than the Earth, and the Earth more than the far ocean" is enough). The chart is for an idealised coast with a 3.2 m spring range and 1.2 m neap range; real coasts vary a lot, and some have one tide a day. Play a day at the beach ignores the moon's movement during the day (which makes real tides about 50 minutes later each day).
Explaining the second bulge on the far side. When a student predicts one high tide a day, ask how many bulges the board shows and how many the coast passes through.
| What you will see | A question to ask | The fix |
|---|---|---|
| A student says there should be one high tide, when the moon is overhead. | How many bulges does the board show? | Two: one towards the moon and one on the far side, so two high tides as the Earth turns. |
| A student thinks spring tides are a season. | How often does the chart show the biggest tides? | About every two weeks: at new and full moon. |
Stretch: Why are the tides at full moon about as big as those at new moon, even though the sun is on opposite sides?
Support: Give a four-picture strip (new, first quarter, full, last quarter) to label spring or neap.
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 are there two high tides a day?". The idea: Tides: I can explain tides as caused by the moon's gravitational pull and distinguish spring from neap tides by moon position. What understanding looks like: - Explains tides as caused by the moon's gravitational pull - Correctly identifies spring and neap tides - Links spring and neap tides to moon positions Mistakes students often make here: - A student says there should be one high tide, when the moon is overhead. - A student thinks spring tides are a season. 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 (Seasons), 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 are there two high tides a day?".
When do spring tides happen, and why are they bigger?
At new and full moon, when the sun and moon are in line, so their pulls on the oceans add together.
This completes AC9S7U03. Later: gravity and orbits (AC9S7U04), and First Nations knowledge of the moon and tides from local sources.
In class: real tide tables; compare tide heights with moon phases over a month.