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Oxbow Lake The water cycle. Waterfalls Most rivers do not have a waterfall. This is because waterfalls only form where the river flows over flat bands.

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Presentation on theme: "Oxbow Lake The water cycle. Waterfalls Most rivers do not have a waterfall. This is because waterfalls only form where the river flows over flat bands."— Presentation transcript:

1 Oxbow Lake The water cycle

2 Waterfalls Most rivers do not have a waterfall. This is because waterfalls only form where the river flows over flat bands of soft and hard rock. Rivers cannot cut through hard rock easily, but once they do, the softer rock below is rapidly removed. As the river water (and the pebbles it is carrying) falls down the face of a waterfall, it falls faster and faster. When it reaches the foot of the fall, it has great energy.

3 Meander Rivers flow in channels. Most rivers cut a single deep channel in a muddy bed. This channel winds its way across the flat floor of a valley. A large curve in a river is called a Meander. As water flows around a curve it gets thrown to the outside of the curve, rather like people on a spinning fairground ride feel themselves thrown outwards as the spin increases. The river can scour its channel most quickly where it flows fastest, that is, near the outside of a bend. On the inside of the bend the water flows much slowly.

4 Oxbow/ Oxbow Lakes Oxbow are narrowed-necked loops of a river. Oxbow lakes are Oxbows that have been abandoned by a river, but still contain water. A Meander may grow into a very narrow-necked loop called an oxbow. Oxbows usually do not survive long. This is why. As a river goes round a tight bend of an oxbow, the oxbow acts as a natural brake on the water. This makes little difference for normal flows, but after a storm, when the river is running high, the tightness of an Oxbow bend tends to make the water pile up rather than flow freely. The best way of spotting Oxbows and Oxbow lakes is from the air, but they are also sometimes show on maps.

5 The Water Cycle Click to try the quiz

6 Quiz!!! Question 1- Do most rivers have a waterfall? A) Yes they do B) No they don’t C) Not many

7 Question 2!! What are Oxbow lakes? A) They are a part of a lake that is separate but still contains water B) It is a part of a river that is a bend

8 Question 3!!! In the water cycle what heats up the water? A) A torch B) The sun

9 Try again!!! Click to go back

10 Try again!!!! Click to go back

11 Try again!!! Click to go back

12 Well done!!! You completed the quiz

13 By Naomi Scott


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