Do you need to memorize Piaget's stages for a test?  You've found what you're looking for.  I'll use some familiar mnemonics ("1 is a bun", etc.) and some wacky images to get those stages - and what during them - into your mind.  You'll be able to remember when object permanence occurs, when children are capable of asiimilation and accomdation, abstract and logical thinking, conservation of energy - it's all here.  Take the time to watch this video, learn about mnemonics and memorize Piaget's stages of cognitive development once and for all!