WALT understand earth systems for sea week. Context: moons, tides and ocean currents
Fact Card#1: How does water move on the surface of the ocean? The water in the ocean is constantly moving. On the surface water moves in the form of waves.
Fact Card#2: How does water move below the surface of the ocean? The water in the ocean is constantly moving. Below the surface the water moves in great currents.
Fact Card #3: What are the two types of ocean currents? The two currents are the surface current and the deep current currents
Fact Card #4: Define ocean currents. Ocean currents are moving streams of water within the ocean.
Fact Card #5: Define the ‘surface current’. The surface current is where currents move on or near the surface of the ocean. There is a cold and a warm current.
Fact Card #6: List the factors which control the surface currents. Three factors that control the surface currents are the air currents, earth's rotation and location of continents.
Fact Card#7: Which factors affect the flow of ocean surface water? Global wind belts are a major factor affecting the flow of ocean surface water.
Fact Card#8: How are deep currents generated in the ocean? The difference in the water density due to the temperature gradient moves the water creates in the deep currents.
Fact Card#9: Write down the characteristics of cold and warm water. Cold water is more dense and it sinks and moves. Warm water is less dense and it rises up.
Fact Card #10: Which ocean currents travel faster? Surface currents travel much faster than deep ocean currents.
Fact Card #11: Write the factors that cause the deep currents. Deep currents are caused by changes in the temperature, how salty the water is and the density of the water.
Card #12: How do the Sun and the Moon cause the ocean.The gravitational pull of the moon and the sun is also an important factor to the force to cause the ocean currents.
Fact Card #13: Give the definition of wave. A wave is a rhythmic movement that carries energy through matter or space.
Fact Card#14: What are the causes of waves? Waves are caused by wind, earthquakes and gravitational force of the moon and the sun
Fact Card#15: List the characteristics of a wave. The crest, through, wavelength, wave height, are parts of the wave.
Fact Card#16: Write the parameters on which the wave height is dependent. The wave height depends on the wind speed, distance over which the wind blows and the length of time the wind blows.
Fact Card #17: What happens during tide? The tide is a periodic rise and fall of the sea level under the gravitational pull of the sun and the moon.
Fact Card #18: What do you mean by high tide? High tide is when the water level is at its highest.
#19: What do you mean by low tide? Low tide is when water level is at its lowest.
Fact Card #20: How does the Moon’s gravity pull ocean water? The moon's gravity pulls the water on the earth towards it. The water moves up into a slight bulge on the side of the earth that faces the moon.
Fact Card#21: What is the cycle duration of high/low tide? Generally one low tide/high tide cycle takes at every 12 hours and 25 minutes.
Fact Card#22: Define tidal range. The difference in ocean level between the high tide and the low tide is called a tidal range.
Fact Card#23: When does spring tide occur? Spring tides occur when the earth, sun and the moon are in a line.
Fact Card #24: Which tides occur during full/new moon? Spring tides occur during the full moon and the new moon.
Fact Card #25: When does neap tide occur? Neap tides occur when the moon and sun are perpendicular to each other.
Fact Card #26: Which tides occur during the quarter moon? Neap tides occur during quarter moon and sun are perpendicular each other
Fact Card #27: Which tides are known as weak tides? Why? Neap tides are weak tides because of the gravitation forces of the moon and the sun counteract each other tidal forces
Fact Card#28: Which tides are known as strong tides? Why? Spring tides are strong tides because the moon and the sun's gravitational force combined to create a strong tide.
