Here is a resource with a descriptive approach to explaining the scientific method. It's simple, but effective for both introduction and reinforcement of this concept. 

The story of Ruby Bridges and the case of Brown vs. The Board of Education are fantastic tools for discussing the concept of separate but equal. Kids tackle some big questions about what is fair, what is civil, and what rights or laws...

Elementary learners listen to a story, then sort objects from largest to smallest at six different stations around the classroom. Adaptable for a large range of age and ability groups. 

Everybody wins when you play Algebra Four. Players solve linear and quadratic equations to earn pieces on the Algebra Four game. Make a row of four pieces and you win the game. But everyone gets practice with solving equations, so really...

Word problems are great for engaging critical thinking skills, and word problems involving money increase a child's financial literacy. Boost your critical and financial thinkers with a multi-step word problem involving money and problem...