🔬 Science
Summer leaf, autumn leaf: drag and see
A birch leaf and a rowan leaf move from summer to autumn. The green fades from both. But only one leaf makes a new colour.
Green: chlorophyll
Yellow: hidden all summer
Red: newly made in autumn
Empty space: no red on the strip
1Summer: chlorophyll makes both leaves green
2Autumn: the tree breaks down the green
3Birch turns yellow, rowan makes new red
4The coffee-filter strip: a green leaf has no red