Students match up beginning of sentences with the ends of sentences. The sentences include vocabulary words and definitions, how to separate different materials, and what happens to the physical properties in mixtures and solutions.
I print the cards on card stock, cut them out, and rubber band them together before class. That way I can use the cards for several years to come. I often use this activity as a warm up, and students that finish quickly become "expert checkers" to help check the rest of the class.