Worksheet on Plate Tectonics focusing on Continental Drift and Seafloor Spreading, including a diagram and questions.

Let’s work through this step by step.

---

Part 1: Fill in the blanks using the word bank

Word bank:
Pangaea, Arctic, rock, continents, Africa, seafloor spreading

We’re reading about Alfred Wegener and his theory of continental drift.

1. “Alfred Wegener was one of the first people to suggest that all of the ___ were joined together in the past.”
→ He talked about landmasses — so continents fits here.

2. “He called the one large continent ___.”
→ That’s his famous supercontinent name → Pangaea

3. “For example, similar fossils have been found in South America and ___.”
→ This is a classic piece of evidence — matching fossils between South America and Africa

4. “Also, fossils of warm weather plants have been found in the ___.”
→ Warm plant fossils in a cold place? That’s the Arctic — which used to be warmer!

5. “Similar ___ structures exist in the Appalachian Mountains and in Greenland and western Europe.”
→ These are mountain ranges made of same kind of stone → rock structures

6. “But until clues on the ocean floor led to Harry Hess’s theory of ___, scientists could not think of how the continents might move.”
→ The mechanism for movement came from the ocean floor → seafloor spreading

✔ So Part 1 answers:
1. continents
2. Pangaea
3. Africa
4. Arctic
5. rock
6. seafloor spreading

---

Part 2: Match letters A–D to statements 7–10

Look at the diagram (even though we can’t see it, we know standard seafloor spreading diagrams):

- A = rising molten rock at mid-ocean ridge
- B = sideways push moving mantle with it
- C = new seafloor cooling and sinking away from ridge
- D = old seafloor subducting or sinking back down

Now match:

7. “Molten rock flows onto the seafloor and hardens as it cools.”
→ That happens after it rises — likely C (new seafloor forming)

8. “Hot, molten rock is forced upward toward the seafloor at a mid-ocean ridge.”
→ That’s the initial rise → A

9. “New seafloor moves away from the ridge, cools, becomes denser, and sinks.”
→ That’s the aging process → D (or maybe C then D — but typically D shows sinking/subduction)

Wait — let’s think carefully based on typical labeling:

In most diagrams:
- A = upwelling magma at ridge
- B = convection current pushing sideways
- C = new crust forming and spreading out
- D = old crust sinking into mantle

So:

7. Molten rock flows onto seafloor and hardens → that’s when new crust forms → C

8. Hot molten rock forced upward → A

9. New seafloor moves away, cools, sinks → that’s later stage → D

10. Molten rock pushes sideways in both directions as it rises, moving mantle with it → that’s the convection flow → B

✔ So Part 2 matches:
7. C
8. A
9. D
10. B

---

Final Answer:

1. continents
2. Pangaea
3. Africa
4. Arctic
5. rock
6. seafloor spreading
7. C
8. A
9. D
10. B