★Cause and Effect
Grade 2 Reading Worksheet - Challenge Me
Read the text. Circle the best answer.
Read this first
How a River Carries Sand
A river may look calm, but it is always moving rock and sand.
Rain and melting snow run down the mountainsides into small streams. The water flows downhill, because gravity pulls it toward lower ground.
As water rushes along, it rubs against rocks on the riverbed. Rocks bump into each other too. Over many years, this wears big rocks down into pebbles, and pebbles into grains of sand. This slow wearing away is called erosion.
Fast water can lift sand and carry it along. That is why rivers often look muddy after a big storm. More rain makes the water flow faster, so it can carry more.
When the river reaches flat land, it slows down. Slow water cannot hold as much, so some sand drops to the bottom. Heavy pebbles drop first, and fine mud travels the farthest.
At last, the river flows into the sea. There, the water spreads out and slows even more. The rest of the sand settles near the river's mouth. Over a very long time, the sand piles up and can form new land.
Why does river water flow downhill?
- The wind pushes it toward the big sea.
- Melting snow pushes it from behind it.
- Gravity pulls it toward lower ground.
What causes big rocks to wear down into sand?
- Water and rocks rub and bump them for many years.
- The sea piles them up near its edge year after year.
- Heavy rain cracks them all in one big storm.
Why do rivers often look muddy after a big storm?
- The river slows down and drops all of its sand.
- The sea pushes mud back up the river.
- Faster water lifts and carries more sand.
What happens when the river reaches flat land?
- It lifts more sand from the riverbed again.
- It speeds up and carries more sand along.
- It slows, and some sand drops to the bottom.
