Maya's Flashlight Test
In July it is summer in Canada and deep winter in Chile. Both are on the same planet, the same distance from the Sun, on the same day.
How can two places on one planet have opposite seasons at the same moment?
Page 1
Science · Grade 6 Science
Chapter 1: Earth, Sun, and Moon
It is the tilt, not the distance.
In July it is summer in Canada and deep winter in Chile. Both are on the same planet, the same distance from the Sun, on the same day.
How can two places on one planet have opposite seasons at the same moment?
Make your guess to turn the page.
Still to come: 10 pages · Words to Know · What We Learned · 4 questions · Explain It in Writing · Ask and Wonder
The idea this lesson is working on — Most children, and many adults, believe summer is when Earth is closer to the Sun. It feels obvious: closer to a fire is warmer. The book lets the flashlight data carry the angle idea first, then brings in the two facts distance cannot survive — Earth is closest in January, and the hemispheres have opposite seasons. Ask: if distance caused summer, what season would Australia have in July?
The hemispheres are opposite — When the northern hemisphere leans towards the Sun it is summer there and winter in the south. If distance caused seasons, both hemispheres would have summer at the same time — and they do not. Longer days add to the effect: the hemisphere leaning toward the Sun gets more hours of steep light.
About the numbers — At 30° the lit patch is 1 ÷ sin 30° = 2 times the area of the 90° patch, so each square gets half the light; Maya's 3.0 °C against 6.0 °C matches. The noon Sun heights, 73° and 27°, are those at 40° north on the solstices. Real warming also depends on day length and on what the ground is made of, which is part of why the flashlight is a model and not a forecast.