Where do the yellows and oranges come from?

All summer, a leaf has yellows and oranges inside it too. But there's so much green that it hides them. When the green goes, the yellows and oranges finally show. Some trees also make bright new reds in autumn.

Then why do the leaves fall off?

As the food-making stops, the tree grows a special layer of cells where each leaf joins its twig. Slowly, that layer cuts the leaf loose. The tree seals the spot, leaving a tiny scar. Then a puff of wind, and down the leaf floats.

Why do leaves change colour?

Roo answers for ages 4–11, then goes 2 steps deeper each time a child asks why.

Roo says

All summer, leaves are full of a green stuff called chlorophyll. It helps the tree make food from sunlight. In autumn, the days get shorter, and the tree stops making the green. As the green fades away, yellows, oranges and reds show up instead.

For ages 4–7

Checked against Why do leaves change color? (NOAA SciJinks)
Where do the yellows and oranges come from?

All summer, a leaf has yellows and oranges inside it too. But there's so much green that it hides them. When the green goes, the yellows and oranges finally show. Some trees also make bright new reds in autumn.

For ages 6–9

Checked against Why leaves change color (SUNY ESF)
Then why do the leaves fall off?

As the food-making stops, the tree grows a special layer of cells where each leaf joins its twig. Slowly, that layer cuts the leaf loose. The tree seals the spot, leaving a tiny scar. Then a puff of wind, and down the leaf floats.

For ages 8–11

Checked against Why leaves change color (SUNY ESF)