With the current focus on constructivist perspectives, science demonstrations have fallen out of favor in some circles. Demonstrations are easy to do and offer many benefits and unique opportunities in the constructivist classroom. With careful use, demonstrations can be powerful teaching tools. A wonderful quality of a demonstration (or a series of demonstrations) is that it can be used to clearly present a concept, the fundamental cornerstone of a lesson. When carefully selected, developed, and presented, a demonstration can make many concepts meaningful and authentic. Figure 1 describes some effective demonstrations to explore the properties of air with students. Young children have a difficult time understanding the notion of air pressure. Diagrams with arrows representing pressure help students to visualize in a concrete way that which they may be unable to observe directly. Teachers should keep in mind that students will revisit these scientific principles at higher grades, if the interest is generated early.