1. Ocean Explorers and Navigators

2. I. Buoyancy A. Most archeological evidence points to a very early beginning in the relationship between people and the sea. B. To effectively travel by water one needs a boat that floats and that can be moved by human power or wind power.

3. I. Buoyancy an ancient Greek scientist was the one who discovered that floating objects are supported by an upward force called buoyancy.C. Archemedies an ancient Greek scientist was the one who discovered that floating objects are supported by an upward force called buoyancy. 1. To Float: object displaces a mass of water equal to the mass of itself & has a low density

4. If Density changes…

5. Now we know how to float let’s get on a boat!!

6. II. Early Sailors: Polynesians A.Polynesians in B.C. 1500 used A.Polynesians in B.C. 1500 used double canoe made of two hulls (55ft) connected by lashed crossbeams B.Developed a highly sophisticated navigation system based on stars, ocean swells, flight patterns of birds to find their way over the open ocean

7. Outrigger canoe

8. III. Early Sailors: Greeks, Phoenicians, & Egyptians A.A. Mediterranean peoples developed large vessels for military and trading purposes on the Mediterranean Sea. –1. Bireme &Triremes B. Their vessels made use of a square sail that could not sail against the wind.

9. IV. Early Sailors:The Vikings A. The invention of the long boat, and a temporally favorable climate, allowed the vikings of Norway and Sweden to explore and settle Greenland, Iceland, and Newfoundland. B. Their boats were stealthy troop-carriers. They could cross the open oceans under sail and then switch to oars for lightning-fast hit- and-run attacks on undefended towns and monasteries

11. V. Early Sailors: Europeans A. Europeans were late to the game of marine exploration, but when they arrived they did so with missionary zeal and lust for gold. B. They built bigger, wider, and much heavier three-masted sailing vessels capable of traveling great distances. 1. Magellan completed the first circumnavigation of the planet with such boats. 2. Columbus completed a voyage to & from Bahamas

13. VI. Why Did They Explore? A sense of adventureA sense of adventure Opportunities to expand trade routesOpportunities to expand trade routes Conquer new landsConquer new lands Obtain great wealthObtain great wealth

14. VII. Early Navigational Technology PeopleItemWhat it did? PolynesianStick Chart Rocks & Sticks – very accurate for the time Chinese 1 st compass Balance a lodestone in a bowl of water & oil & used it to point north EgyptiansLead lineMeasure depth EuropeChip logMeasuring speed

16. A.The Beagle - 1831,British ship carried Charles Darwin around the world for 4 years. 1. Their work consisted of drawing maps, making observations, and collecting plants and animals. B.The H.M.S. Challenger - 1872, journey around the world. Goal was to gather as many observations of oceanic phenomena as possible. 1. Scientists took readings on salinity, temperature and density, which contributed to the rapidly growing understanding of physical oceanography. IIX. From Exploring to Science

17. Home Work due 9/6 Draw & Design a boat Include: -What features allow the boat to stay buoyant? -What technology is found on your boat? How is each item used? -How is your boat powered/controlled? (man or wind or motor) -What is the purpose of your voyage?