Eclipse Geometry: Shadows in Space

Name: ________________________________ Section: __________ Date: __________

Station: __________ Group members: ________________________________________________

Goal: Use the demo to make a claim supported by (1) at least one number/readout and (2) at least one sanity check.

Station card: Eclipse Geometry (6–8 minutes) Demo setup: Use New Moon and Full Moon buttons; drag near/far from nodes.
Tip: Click Station Mode to add snapshot rows and print/copy your table.

Your station artifact (fill in):

1. Control(s): phase angle $\Delta$, node proximity (nearest-node distance or $|\beta|$), tilt $i$
2. Observable(s): eclipse type (none/partial/central; penumbral/umbral/total)
3. Governing relationship: write “eclipse requires syzygy + small $|\beta|$” in words
4. Sanity check: what happens when $i=0^\circ$?
5. Connection sentence: “This connects to angular size because…”

Word bank + sanity checks Word bank:

• Syzygy: Sun–Earth–Moon aligned (New Moon for solar eclipses; Full Moon for lunar eclipses).
• Node: where the Moon’s orbit crosses the ecliptic plane.
• Ecliptic latitude $\beta$ (degrees): how far the Moon is above/below the ecliptic plane.
• Inclination $i$ (degrees): tilt of the Moon’s orbit relative to the ecliptic plane.
• Near a node: small $|\beta|$ (and/or small “nearest node” distance) at syzygy.

Sanity checks:

• You need BOTH: (1) New/Full Moon and (2) near a node (small $|\beta|$). One condition alone is not enough.
• If $i=0^\circ$, then $\beta=0^\circ$ always → eclipses happen every month.
• Changing Earth–Moon distance can change whether a solar eclipse is total or annular (size matters too).