Physical Weathering
A giant rock in the desert is smooth during the day but cracks at night.
The desert gets:
What MOST LIKELY caused the cracks?
rocks expanded in heat and contracted in cold repeatedly until they cracked.
A river and a glacier both move Earth materials.
One moves FAST.
One moves SLOWLY.
Which one can still cause powerful erosion even though it moves slowly? WHY?
The glacier because its huge weight scrapes and carries rocks.
A river suddenly slows before entering a lake.
What will MOST LIKELY happen to the sediments?
They will be deposited.
You see:
What clue suggests erosion happened here?
Rocks became smooth from rubbing during movement.
Which process changes the SIZE of rocks but NOT their LOCATION?
Physical weathering
A student says:
“Rain always causes chemical weathering.”
But after a snowstorm, a road suddenly has many broken rocks.
Use evidence to prove the student is wrong.
Water froze in cracks, expanded, and broke the rocks apart physically.
After heavy rain, muddy water rushes downhill.
The NEXT day, tree roots are sticking out of the ground.
What happened to the soil?
The soil eroded and washed away.
Three objects move in water:
The water slows down.
Which material settles LAST? WHY?
Clay because tiny particles stay suspended longer.
A canyon has steep sides and a river at the bottom.
What MOST likely helped form the canyon?
Long-term water erosion.
Which process depends MOST on movement?
erosion
Two identical rocks are placed:
Ten years later, one rock is badly cracked.
Which rock changed more? Explain WHY using physical weathering.
The rock near roots because roots grow into cracks and force rocks apart.
A beach loses sand every winter but gains sand every summer.
What does this tell you about erosion?
Erosion changes depending on waves, storms, and seasons.
After a flood, a farmer’s field becomes MORE fertile instead of ruined.
How can deposition HELP farmers?
Floodwaters deposit nutrient-rich soil.
A scientist discovers layers of sand far from any beach.
What could this reveal about Earth’s past?
Water or wind may once have deposited sediments there
A cliff loses rocks during a storm.
Months later, a beach grows larger nearby.
Connect ALL the processes involved in order.
Physical weathering → erosion → deposition
An astronaut visits two planets:
Which planet will probably have MORE cracked rocks over time? Why?
Planet A because freezing and thawing breaks rocks apart.
A student claims:
“Wind cannot move large rocks.”
Another student disagrees.
Who is MOST correct? Explain carefully.
The second student because wind can slowly wear down rocks with blowing sand and move smaller rock particles.
A student says:
“Deposition only happens in rivers.”
Give TWO examples proving this is false.
Sand dunes formed by wind; ocean waves forming beaches; glaciers dropping sediments.
Two mountains:
Which mountain has probably experienced MORE weathering? Why?
Mountain B because weathering smooths edges over time.
Earth suddenly had NO wind, NO water movement, and NO glaciers.
Which Earth process would continue MOST?
Explain.
Physical weathering could still continue from temperature changes and plant roots.
A mountain climber says:
“Tiny drops of water can break huge rocks.”
At first this sounds impossible.
Explain how tiny drops can actually destroy mountains over time.
Water enters cracks, freezes, expands, and repeats for thousands of years, slowly breaking rocks into smaller pieces.
You are designing a town near a steep hill.
Which is SAFER from erosion?
Defend your answer like a scientist.
The planted hill because roots hold soil together and reduce erosion.
A river carries sediments for hundreds of kilometers.
Why doesn’t it drop all sediments immediately?
Fast-moving water has enough energy to keep materials moving until it slows down.
A student says:
“If weathering stopped, erosion would stop too.”
Do you agree? Explain deeply.
Mostly yes, because erosion needs weathered materials to move, though existing sediments could still erode for some time.
You must protect a coastal city from disappearing beaches.
Would you focus MORE on stopping:
Defend your answer using evidence.
Erosion, because sand is being removed faster than it is deposited.