Could also connect a bunch of locks and put all the keys on a key ring. Lots of pictures of latch, lock, etc ideas for montessori type preschool. This lock one could be made with 2 boards, some o-rings, and some locks from Dollar Store.
Indoor Activities for Kids: Homemade Lava Lamps. Vegetable oil, a about of the water bottle, then water. 10 drops of food coloring. Then take a alkaseltzer tab and break it into 4 pieces. Drop one in at a time and wait for each to dissove!
Perfect for some nature study with toddlers and older kids watching frog spawn develop into tadpoles and then frogs. Find out how to keep, feed and care for them in home as well as some other fun ideas for learning with nature this Spring.