Complex fluids are special kinds of mixtures that have characteristics of more than one phase of matter. In this video, the combination of cornstarch and water resulted in a substance that exhibited the properties of a solid and a liquid depending on the amount of pressure or force applied to it. These types of fluids that don’t behave like what we think of as “normal” fluids are called non-Newtonian fluids. Many non-Newtonian fluids are made of polymers, long chains of repeating molecules that give the fluid unusual physical properties such as flexibility and strength.
Although scientists do not fully understand the mechanism behind lightning, they think it is created when particles collide with other particles, causing them to generate and build up large amounts of static charges. The same basic process that creates lightning also occurs on a much smaller scale when you get a shock after shuffling across a carpet and touching a doorknob. What is giving you a shock is static electricity. In this set of activities, students will generate static electricity by rubbing or “charging” a balloon.
Many popular sports, including basketball, are based upon the use of a ball. Yet each type of ball is easily associated with a specific sport, because each ball is distinctly different. A ball’s performance is directly influenced by its characteristics or properties. For example, the oval shape of a football allows it to travel farther in the air than a ball that is round. In this activity, students will explore the properties of various balls from different sports, and discuss why the design of each ball is suited to its associated sport.
In this segment, Ira talks with primatologist and anthropologist Jane Goodall about her work in studying chimpanzees, preserving habitats, and what lies ahead for the field of evolutionary science.