Forces in Earth's Crust

Forces that affect changes on Earth

Open Ended

Are volcanoes constructive or destructive force? Explain.

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Our Earth is ever changing. Some of these changes, like the creation of the Grand Canyon, take millions of years to happen, and some of them are catastrophic changes that occur in seconds. These changes to our Earth can be categorized as either constructive forces or destructive forces.

Slow Constructive Forces

Constructive Earth processes are changes that add to the surface of the Earth, and some of them take millions of years to occur. The Hawaiian Islands are a great example of a slow constructive change. These islands have formed over millions of years due to a hot spot volcano. This type of volcano forms over an area in the Earth's crust where the crust is very thin and lava consistently makes its way to the surface.

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Another example of a slow constructive force is the deposition of sediment at the mouth of a river. Water carries sediment down river and as the river becomes more shallow, the sediment is deposited, forming landforms such as deltas.

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Mountains are also an example of a slow constructive force due to two tectonic plates being pushed into each other.​

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​Destructive forces break down land. The two main forces that break down land slowly are weathering and erosion. Weathering is the breaking down of rocks due to forces such as wind and water. The pieces of rock are then moved elsewhere through the process of erosion. Weathering and erosion take millions of years to have an effect on the Earth

Multiple Choice

Weathering is the natural process of

• breaking down rock.
• loosening bits of rock from the soil.
• moving soil to a different location.
• materials settling out of water.

Multiple Choice

One example of erosion is when

• tree roots split apart rock.
• soil builds up at the mouth of a river.
• water carries soil from a garden to a sidewalk.
• moving water makes river rocks smooth.

Multiple Choice

What is weathering?

• When Earth material, like rock, sand, and soil are being carried away from their original location
• When Earth materials are broken down into smaller pieces
• When Earth materials, like rock, sand, and soil, are dropped or deposited into a new location.
• When the Earth changes quickly and it looks different from before.

Multiple Choice

Which rapid process occurs when the plates of Earth shift rapidly and the surface of the ground shakes and rolls causing damage to Earth's surface, like cracks, and other openings, and damage to roads and buildings?

• landslide
• earthquake
• flood
• volcanic eruptions

Multiple Choice

Which of the following describes how a volcanic eruption changes Earth?

• It can cause cracks on the surface of Earth and destroy buildings.
• It can make a volcano larger and add new rocks to the Earth's surface
• It can carry away parts of the Earth and drop them to lower locations.
• It can create valleys and canyons by taking away the Earth a little at a time

Multiple Choice

What event can cause most landslides?

• Too much rain soaking the ground of a mountain and making the soil loose.
• Too much shaking of the Earth's water
• Too much lava coming out of a volcano during an eruption
• Too much wind blowing the side of a mountain.

Multiple Choice

Earth's plates can cause earthquakes, mountain creation and volcanoes.

• True

• False

Multiple Choice

Which of the following is in the picture?

• volcanic eruption
• landslide
• weathering of the rocks
• flood

Multiple Choice

The molten rock BENEATH Earth's surface is called...

• volcano
• crust
• magma
• epicenter

Multiple Choice

A very large ocean wave that is caused by an underwater earthquake is a/an...

• flood
• tsunami
• rockslide
• weathering

Multiple Choice

A/An ________________ is an opening in Earth's crust through which hot ash, gases, and molten rock escape.

• volcano
• fault 
• earthquake
• creep

Multiple Choice

Molten rock that reaches Earth's surface is called...

• smoke
• lava
• ash
• magma

Multiple Choice

Which describes an earthquake that is very strong to violent?

• not felt by most people
• small objects move
• trees are shaken
• cracks are in the ground

Multiple Choice

What is a way local governments can prevent some damage from a landslide?

• limit where people can build houses
• building supporting walls to change direction of where a landslide would flow
• do not allow businesses to build on mountainsides
• all of the above