Did you know that until the 16th century, mariners and seamen referred to sharks as "sea dogs"? Sharks have actually been around for a long time--many scientists think a variation of the shark existed from over 420 million years ago! Sharks belong to a large group of fish that have a skeleton made of cartilage instead of bone. Because of this, the only fossilized remains of ancient sharks are their teeth.The teeth of sharks grow in constantly to replace older ones that wear out. It is estimated that sharks can lose up to 20,000 teeth in their lifetime. In fact, some ancient sharks had teeth that grew as long as 4 inches.
Want a great example of a shark tooth fossil? Invest in this inexpensive, authentic shark tooth fossil specimen to spruce up your science classroom! Also makes a unique gift, stocking stuffer, or party favor for adults and children alike!
Check out this high-quality gyroscope!
A beautiful desk or bookshelf accessory for the reading fanatic in your family!
This smaller transportable Van de Graaff Generator will easily fit in any classroom!
Use this temperature-controlled soldering station for a variety of soldering applications!
Discover a world of kaleidoscopic effects within this perfectly clear prism of the Light Crystal!
This adapter-powered butterfly uses Flexinor wires to create a realistic visual effect!