The Rubber Frog is a variation of the well-known rubber duck. Like the original rubber duck, the Rubber Frog is a hollow, light-weight toy that floats above water. This can be achieved through the concept of buoyancy. The fluid exerts an upward force created by fluid pressure against the rubber frog, keeping it afloat. The magnitude of this upward force is equivalent to the weight of the displaced fluid. In this case, the displaced fluid's weight is much greater than the weight of the Rubber Frog because the Frog is hollow. A second physical concept at work here is surface tension. Surface tension is the phenomenon of attraction between liquid molecules induced by intermolecular forces. This attraction causes the liquid to minimize its surface area and push back any contacting molecules in the process. This force is dependent on the surface area, such that greater surface area equates to greater force. The Rubber Frog possesses a shape such that surface area is maximized, so the surface tension between the liquid surface and the frog is maximized.
Contrary to its name, the Rubber Frog is not made out of rubber. Instead, it is made from vinyl plastic because not only is plastic more easy to produce, but is also cheaper than rubber. As a benefit, the production costs of the duck can be minimized. Furthermore, plastic can easily sustain its shape and is durable. The primary manufacturing process for the Rubber Frog is mold injection, which involves the injection of melted plastic into a hardened metal mold under high pressures. The production of the molds (injection mold and ejector mold) is the only expensive step in the operation. On the other hand, injection molding is a relatively cheap and simple process, so the production costs are relatively low. The retail price of this Rubber Frog is projected to be somewhere within the range of two USD and four USD.
Children of all ages can enjoy the Rubber Frog. There are no small pieces in this toy which may endanger infants. Children can play with the Rubber Frog wherever water is easily accessible. This includes bathtubs, pools, beaches, sinks, and buckets. Children can watch the Rubber Frog float and glide across liquid surfaces. Regardless of the frog's location, it will always float back to the top of the water to greet children. It can also serve as an adorable pet to children. Most importantly, Rubber Frogs do not require any feeding, so they are relatively easy to take care of.
Source:
http://www.rubaduck.com/FAQ/rubber_duck_faq-table-of-contents.htm
http://www.what-is-injection-molding.com/Default.aspx?tabid=36