Seasons: Why Tilt Matters

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: Seasons (6–8 minutes) Demo setup: defaults $\rightarrow$ then click June Solstice and December Solstice.
Tip: Click Station Mode to add anchor-date rows and print/copy your table.

Your station artifact (fill in):

1. Control(s): tilt $\varepsilon$, day of year, latitude $\phi$
2. Observable(s): day length, noon altitude, season labels
3. Governing relationship: write one sentence connecting $\varepsilon \rightarrow \delta \rightarrow$ day length
4. Sanity check: what happens when $\varepsilon=0^\circ$?
5. Connection sentence: “This matters for eclipses/phases because…”

Word bank + sanity checks Word bank:

• Axial tilt $\varepsilon$ (degrees): tilt of Earth’s spin axis relative to its orbital plane.
• Solar declination $\delta$ (degrees): the Sun’s “latitude” on the sky; it sets where the noon Sun is highest.
• Noon altitude (degrees): the Sun’s height above the horizon at local noon.
• Day length (hours): total daylight time in a day at a latitude.
• Equinox: $\delta \approx 0^\circ$; day and night are about equal.
• Solstice: $|\delta|$ is largest; one hemisphere has its longest day and highest noon Sun.

Sanity checks:

• If $\varepsilon=0^\circ$, then $\delta=0^\circ$ all year $\rightarrow$ day length stays about 12 h (no seasons).
• June vs December: at the same latitude, the hemisphere facing the Sun has longer days and a higher noon Sun.
• Perihelion is in early January, so Earth–Sun distance does not line up with Northern Hemisphere summer.