Doraemon Specials (1970) : 3x16

Suneo, after getting good test scores, tries to use his newfound confidence to get back at Gian and Nobita. He decides to help them and uses some of Doraemon's gadgets, but then he accidentally sends them into an other world where he can learn about the world, according to the summary. He uses the gadgets to gain the attention of the insect-like humans and then tells them about the planet's history. After this incident, Doraemon and his friends get together with the insect-like humans to go and find the other world, where he can learn about the world.