Ocean Explorers and Ocean Explorers and NavigatorsNavigators

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.

I. Buoyancy

• C. Archemedies an ancient Greek an ancient Greek scientist was the one who discovered scientist was the one who discovered that floating objects are supported by an that floating objects are supported by an upward force called upward force called buoyancy.buoyancy.

1. To Float: object 1. To Float: object displaces a mass of displaces a mass of water equal to the mass of itselfwater equal to the mass of itself & has a & has a low densitylow density

• If Density changes…

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

II. Early Sailors:II. Early Sailors:PolynesiansPolynesians

A.A. Polynesians in B.C. 1500 Polynesians in B.C. 1500 used 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

Outrigger canoe

III. Early Sailors: Greeks, III. Early Sailors: Greeks, Phoenicians, & EgyptiansPhoenicians, & 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.

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

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

VI. Why Did They VI. Why Did They Explore?Explore?

• A sense of adventureA sense of adventure

• Opportunities to expand trade Opportunities to expand trade routesroutes

• Conquer new landsConquer new lands

• Obtain great wealthObtain great wealth

VII. Early Navigational Technology

People Item What it did?

Polynesian Stick ChartRocks & Sticks – very accurate for the time

Chinese 1st compassBalance a lodestone in a bowl of water & oil & used it to point north

Egyptians Lead line Measure depth

Europe Chip log Measuring speed

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

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?