BELLWORK11/12-11/13 A group of science students conducted an investigation to find out if people born in a particular season are more likely to have asthma. They gave a survey to 200 students asking them for their birthday and whether or not they have asthma. The table below shows the data they collected. A group of science students conducted an investigation to find out if people born in a particular season are more likely to have asthma. They gave a survey to 200 students asking them for their birthday and whether or not they have asthma. The table below shows the data they collected. Why is “the season in which the greatest percentage of students with asthma was born” the best evidence that people are more likely to have asthma if they are born in a particular season? What would make this experiment better? Why is “the season in which the greatest percentage of students with asthma was born” the best evidence that people are more likely to have asthma if they are born in a particular season? What would make this experiment better? Season# of students born in the season # of students with asthma Fall523 Winter608 Spring407 Summer482

LITHOSPHERE’S PLATES The lithosphere is broken up into many plates called “tectonic plates” The lithosphere is broken up into many plates called “tectonic plates” Scientists are not sure how or when these plates formed Scientists are not sure how or when these plates formed

TECTONIC PLATES Tectonic plates fit together like one large jigsaw puzzle Tectonic plates fit together like one large jigsaw puzzle Compare it to an hard- boiled egg shell broken into many pieces Compare it to an hard- boiled egg shell broken into many pieces Most large tectonic plates include both continental crust and oceanic crust Most large tectonic plates include both continental crust and oceanic crust

HMMMMM? LET US PONDER… 1-Draw Conclusions: Suppose you are looking at a scene that has mountains near an ocean. Where do you think the crust would be thickest? Thinnest? Why? 1-Draw Conclusions: Suppose you are looking at a scene that has mountains near an ocean. Where do you think the crust would be thickest? Thinnest? Why? 2-Hypothesize: What would Earth look like if most of its crust was above sea level? 2-Hypothesize: What would Earth look like if most of its crust was above sea level? 3-Predict: You have learned that Earth’s lithosphere is made up of many plates. How do you think this fact might help scientists solve the mystery of the moving continents? 3-Predict: You have learned that Earth’s lithosphere is made up of many plates. How do you think this fact might help scientists solve the mystery of the moving continents?

tectonics/ tectonics/

THEORY OF PLATE TECTONICS- EVIDENCE FROM THE SEA FLOOR The ocean floor has HUGE underwater mountain ranges called mid-ocean ridges. The ocean floor has HUGE underwater mountain ranges called mid-ocean ridges. They look similar to the seams of a baseball on each ocean’s floor They look similar to the seams of a baseball on each ocean’s floor

SEA-FLOOR SPREADING Ridges form along cracks in the crust. Ridges form along cracks in the crust. Molten rock rises through these cracks, cools, and forms new oceanic crust…STOP-Where does this molten rock come from??? Molten rock rises through these cracks, cools, and forms new oceanic crust…STOP-Where does this molten rock come from??? The old crust is pulled away to make room for new material and the sea floor slowly spread apart (these areas are called spreading centers) The old crust is pulled away to make room for new material and the sea floor slowly spread apart (these areas are called spreading centers)

AGE OF THE SEA FLOOR Rock samples have revealed that the youngest rocks is the closet to the ridge, while the oldest rocks are furthest away Rock samples have revealed that the youngest rocks is the closet to the ridge, while the oldest rocks are furthest away These samples showed that even the oldest ocean floor is young—only about 160 to 180 million years old. These samples showed that even the oldest ocean floor is young—only about 160 to 180 million years old.

CAUSES OF PLATE MOVEMENT Rocks in the asthenosphere move by convection Rocks in the asthenosphere move by convection Convection is the energy transfer by the movement of a material Convection is the energy transfer by the movement of a material

CONTINUED… The hot, soft rock rises, cooled, and sinks then is heated and rises again. The hot, soft rock rises, cooled, and sinks then is heated and rises again. If this rising and sinking continues, it is called a convection current—a motion that transfers heat energy in a material If this rising and sinking continues, it is called a convection current—a motion that transfers heat energy in a material

FORMATIVE #1 What evidence did Wegener gather to support his continental drift hypothesis? What evidence did Wegener gather to support his continental drift hypothesis? Give two types of evidence from the sea floor that prove Earth’s tectonic plates move. Give two types of evidence from the sea floor that prove Earth’s tectonic plates move. Explain how motions in the asthenosphere can move tectonic plates around the Earth. Explain how motions in the asthenosphere can move tectonic plates around the Earth. In what ways are the lithosphere and asthenosphere different? In what ways are the lithosphere and asthenosphere different?