Deception: Hold the photograph upside down, and ask: "Do you notice anything unusual about these dead leaves?". Slowly turn the picture the right way up, point to the frog's eye and ask: "So whose eye is this?". It may take some time to pick out the frog, but it arouses excitement and curiosity about perception, wildlife, camouflage.
The psychology of perception: Our senses can deceive us. Put a stick in water; it looks bent. Draw a straight line, then draw short, left to right diagonal lines across the left side, and right to left diagonals across the right side; it does not look so straight. Cover up the frog's eye. It now looks like autumn leaves, nuts, wood.
Frogs: What does "amphibious" mean? What are amphibious animals? Vehicles? Are all frogs green? (No, this one isn't and some are red.) Where do they live (near water, but some live and breed in trees)? Are they all harmless (their skin can be poisonous)?
Camouflage: Why camouflage (catch prey, avoid predators)? Make a camouflaged coat (with leaves, twigs, etc) for a doll or puppet. Paint a picture of autumn leaves and twigs with something hidden in it. Write a first person story about the frog, starting: "I'll just sit here a bit longer and ..."
Ted Wragg is professor of education at Exeter University