Salt Water vs. Fresh Water • Make a hypothesis about salt water and fresh water. • Make a prediction in words and pictures about what will happen when you pour salt water into fresh water. • SLOWLY, pour the colored salt water into the fresh water. • Record what happens in words and pictures. • Predict what will happen if you reverse the experiment. Do it. Record outcome.
Salt Water vs. Fresh Water 6. Draw conclusions about which water is denser and tell why you think the way you do. 7. What do you predict would happen if you mixed salt into the fresh water and repeated the experiment? Have you changed the density of the fresh water by adding salt to it? 8. Can you make the salt water more dense? How? 9. Would an object float differently in salt or fresh water?
Everybody read to find out: • What oceans are like • What causes ocean currents • The three ways ocean currents can form • Names of different major currents in the ocean • How water moves in a wave • What causes tides
What causes ocean currents? When Earth rotates, the wind blows, or the water changes density Cause Effect currents form.
How does water in a wave move? • All waves carry energy from place to place. • The energy of a wave moves forward across the water (like the motion of a slinky). • The wind also moves the waves (surface currents).
What causes tides? The pull of the moon’s and the sun’s gravity Causes tides to form.
A. Continental Shelf • Continental shelf: the underwater edge of a continent • Extends from the shore to a depth of about 500 feet and has a gentle slope
B. Continental Slope • Continental slope: leads from the continental shelf to the sea floor. • It is steeper, deeper, and narrower than the shelf. • This is about 50 miles from the shore
C. Continental Rise • Continental rise: a buildup of sediment (junk) on the sea floor at the bottom of the continental slope • It is about 65 miles from the shore • Consists mostly of mud and sand
D. Abyssal Plain • Abyssal Plain: at the end of the continental rise and is one of the flattest places on Earth. • Covers almost half of the deep ocean floor Abyssal Plain
E. Seamounts • They are huge underwater mountains that are sometimes found in the abyssal plain. • They are also volcanoes which helps them “grow”. • The Hawaiian Islands are seamounts that have risen above the surface of the ocean.
F. Trenches • a deep valley in the sea floor • Deep “dip” in the ocean that can be up to 5-6 miles below sea level—the deepest points on Earth • Too deep to see sunlight, pitch black, and freezing cold • The deepest trench is the Marianas Trench.
G. Mid-Ocean Ridges • Mid-ocean ridges: chain of mountains that wind along all the world’s major oceans • Formed by molten rock that cooled and hardened.
Everybody read to find out • What is salinity???? • What causes the salinity of the ocean • How waves move • The parts of a wave
The Salinity of the Ocean • The salinity of the ocean is the amount of salt dissolved in the ocean. • Sea water contains salts and other minerals and chemicals. • Most of the minerals in salt water come from Earth’s crust. • Rivers also pick up minerals as they flow over land and carry the minerals into the ocean.
Waves • Waves have four parts. • a. Crest-highest part • b. Trough—lowest part • c. Wave Height—distancefrom the crest to the trough • d. Wavelength—distancefrom one crest to the next crest or one trough to the next trough
Parts of a Wave Wavelength Crest Wave height trough
Waves Continued • Waves are caused by wind. • Breaker waves are waves that break, or crash, along the shore. They are usually foamy. • In a wave, particles move in a circle. • The average depth of the ocean water is about 4 miles.
Science Vocabulary Continental rise Continental slope Seamount Continental shelf Crest Trough Wave length Wave height Tide Breaker Trench Hydrosphere Mid-Ocean Ridges Abyssal Plain