Grade 6 Science Unit 3 Test Ecs

As the depth of snow and ice on a glacier increases beyond 30 to 40 meters, the force of gravity starts to pull the glacier downhill. Gravity is the natural force that attracts objects towards each other, and in this case, it causes the glacier to move under its own weight. This gravitational force is responsible for the slow but continuous movement of glaciers, as they flow downhill due to the pull of gravity.

Continental glaciers are much larger and thicker compared to valley glaciers. Continental glaciers cover large areas of land, sometimes entire continents, while valley glaciers are confined to valleys or mountainous regions. The sheer size and thickness of continental glaciers make them more powerful in terms of their ability to shape the landscape and cause significant erosion. Valley glaciers, on the other hand, are smaller and more localized, resulting in less overall erosion.

Meanders are looplike bends that form in a river flowing across a wide floodplain. As the river flows, it erodes the outer banks and deposits sediment on the inner banks, causing the river to curve and form loops. These loops, known as meanders, are a common feature of rivers in floodplains. Therefore, the correct answer is meanders.

Ocean waves are primarily generated by the wind blowing across the water's surface. As the wind interacts with the surface of the ocean, it transfers some of its energy to the water, causing it to move in a circular motion and creating waves. The strength and duration of the wind determine the size and power of the waves. While tides, rivers flowing into the ocean, and rocks falling into the ocean can also have some influence on wave formation, the primary source of energy for ocean waves is the wind.

As more water flows through a river, its speed will increase. This is because the increased volume of water creates more force, causing the water to flow faster. Additionally, the increased flow of water can also lead to a decrease in friction between the water and the streambed, further contributing to the increase in speed.

Glaciers can only form when more snow falls than melts. This is because glaciers are formed by the accumulation of snow over a long period of time, which then compresses and turns into ice. If the amount of snowfall is greater than the amount of melting, the excess snow can accumulate and eventually form a glacier. Conversely, if more snow melts than falls, the ice will not accumulate and a glacier will not form. The other options mentioned in the question, such as the presence of an ice age or a U-shaped valley, are not necessary conditions for glacier formation.

Landslides, mudflows, slump, and creep are all examples of mass movement. Mass movement refers to the downhill movement of rock, soil, or debris under the influence of gravity. These processes occur when the force of gravity exceeds the strength of the material, causing it to move downslope. Landslides involve the rapid movement of large masses of rock and soil, while mudflows are fast-moving mixtures of water and soil. Slump refers to the sliding of a mass of rock or soil along a curved surface, and creep is the slow, gradual movement of soil and rock downhill.

Mass movement refers to the downhill movement of soil, rocks, and other materials under the influence of gravity. Gravity is the force that pulls objects towards the center of the Earth, causing them to move downhill. It acts as the driving force behind mass movement, causing materials to slide, slump, or flow downhill. While other factors like plucking, abrasion, chemical weathering, erosion, and deposition can contribute to mass movement, gravity is the primary cause that initiates and controls the movement of materials downslope.

When a river flows from an area of harder rock to an area of softer rock, the softer rock is more easily eroded by the force of the water. Over time, this continuous erosion causes the softer rock to wear away, creating a sudden drop in the river's course. This drop is known as a waterfall. The force of the water falling over the edge of the harder rock creates a dramatic and picturesque feature in the landscape.

A stream or river that runs into another stream or river is called a tributary. Tributaries are smaller bodies of water that flow into larger bodies of water, such as rivers or lakes. They contribute to the overall flow and volume of the main river or stream. Tributaries can come from various sources, such as springs, smaller streams, or even rainfall runoff. They play a crucial role in the water cycle and are important for the overall health and sustainability of the larger water system.

Deposition is the correct answer because it refers to the process by which sediment is deposited or laid down in a new location. This can occur when wind, water, or ice lose energy and are no longer able to transport the sediment, causing it to settle and accumulate in a new area. Deposition is an important geological process that contributes to the formation of various landforms such as deltas, beaches, and dunes.

A ridge of till located at the farthest point reached by a glacier is called a terminal moraine. This is formed when the glacier melts and deposits the sediment it was carrying at its furthest extent. Terminal moraines are often found at the end of a glacier and mark the maximum advance of the ice. They can vary in size and shape depending on the characteristics of the glacier and the terrain it moves over.

When the wind slows down or hits an obstacle, it loses its ability to carry the sand grains and deposits them. This is because the reduced wind speed or the presence of an obstacle disrupts the flow of the wind, causing it to drop the sand particles it was carrying. This process is known as sedimentation and is responsible for the formation of sand dunes and other landforms in deserts and coastal areas.

Deltas are built up by deposition, which is the process of sediment being dropped or laid down in a new location. This occurs when a river or stream carrying sediment reaches a body of water, such as a lake or ocean, and slows down. The decrease in velocity causes the sediment to settle out and accumulate, gradually building up the delta. Deposition is the key process that contributes to the growth and formation of deltas over time.

A fast-flowing river has enough energy to lift and carry sand-sized particles of sediment downstream. The force of the moving water can overcome the weight of the particles, causing them to be lifted off the streambed and transported downstream. This process is known as suspension, where the particles are suspended in the water column and transported by the current.

A stalagmite is a cone-shaped deposit of calcite that builds up on the floor of a cave. Unlike stalactites, which hang from the ceiling, stalagmites form from the ground as mineral-rich water drips down and deposits calcite over time. This process can take thousands of years, resulting in the formation of unique and fascinating geological structures within caves.

Plucking is the correct answer because it refers to the process in which rock fragments freeze to the bottom of a glacier and are then carried away when the glacier moves. This process occurs as the glacier moves over bedrock, causing the rocks to become embedded in the ice and be plucked or torn away from the surface. Plucking is an important mechanism of glacial erosion and helps to shape the landscape by transporting and depositing the rock fragments as the glacier advances and retreats.

Erosion is the correct answer because it refers to the process in which natural forces such as wind, water, or ice transport weathered rock and soil from one place to another. This movement of sediment can occur through various means such as water runoff, wind carrying particles, or glaciers pushing debris. Soil conservation, deposition, and abrasion are not accurate descriptions of this process. Soil conservation refers to efforts to prevent soil erosion, deposition refers to the settling of sediment in a new location, and abrasion is the wearing away of rock surfaces by friction.

After the last ice age, stranded ice blocks left behind by the continental glacier melted and formed kettles. Kettles are depressions or hollows in the ground that are formed when large blocks of ice are left behind by the melting glacier. These blocks of ice become buried by sediment and when they eventually melt, they leave behind a depression or hole in the ground. These depressions can fill with water, forming lakes or ponds, or they can remain dry. Kettles are commonly found in areas that were once covered by glaciers, such as in parts of North America and Scandinavia.

As the slope of a river increases, the speed and force of the water flow also increase. This increased velocity and force allow the river to carry larger sediment particles and erode the surrounding land more effectively. Therefore, the power of the river to cause erosion usually increases when the slope increases.

As gravity pulls water down a slope, its potential energy decreases while its kinetic energy increases. This is because potential energy is the energy an object possesses due to its position or height, and as the water moves down the slope, it loses height and therefore potential energy. At the same time, its kinetic energy, which is the energy of motion, increases as the water gains speed while moving down the slope. Therefore, the potential energy of the water changes to kinetic energy.

A spit is a fingerlike landform that forms when a coastline turns and interrupts longshore drift. Longshore drift is the movement of sediment along the coast caused by waves and currents. When the coastline turns, the direction of the waves and currents change, causing sediment to be deposited in a long, narrow strip of land that extends out into the water. This landform is called a spit.

Loess is the correct answer because it refers to particles of clay and silt that are eroded and deposited by the wind. Loess deposits are typically found in areas with strong winds, and they are known for their fine-grained texture and ability to retain moisture. These deposits are often used for agricultural purposes due to their fertility and ability to support plant growth.

Water at the top of a slope has potential energy. Potential energy is the energy possessed by an object due to its position or state. In this case, the water at the top of the slope has the potential to do work or gain kinetic energy as it flows down the slope. The higher the water is positioned, the greater its potential energy, which can be converted into other forms of energy, such as kinetic energy, as it moves downhill. Therefore, potential energy is the correct answer for this question.

When a river moves sediment and erodes its banks, the type of energy involved is kinetic energy. Kinetic energy is the energy possessed by a moving object or substance. In this case, the river's movement causes the sediment to be carried along and the banks to be eroded. This movement of the river and the sediment is a clear indication of kinetic energy being involved in the process.

Sheet erosion is the correct answer because it refers to the process where water runoff from rainfall flows in a thin, uniform layer over the land, causing the top layer of soil to be gradually removed. This type of erosion is characterized by the removal of a thin sheet of soil from large areas, rather than the formation of distinct channels or gullies. Sheet erosion is commonly observed on sloping land and can lead to the loss of valuable topsoil, which can have detrimental effects on agriculture and the environment.

Karst topography refers to a landscape where a layer of limestone close to the surface erodes into deep valleys, caverns, and sinkholes. The dissolution of limestone by water over time creates these distinctive features. The process involves the gradual dissolution of the rock, leading to the formation of underground drainage systems, caves, and sinkholes. This type of topography is commonly found in regions with abundant limestone deposits and is characterized by its unique geological formations.

Deflation refers to the process by which wind removes surface materials. It occurs when wind erodes and carries away loose particles such as sand and dust, leaving behind a bare surface. This process is commonly observed in arid and desert regions where there is limited vegetation to hold the soil in place. The wind picks up and transports the loose materials, causing erosion and shaping the landscape over time.

The presence of a U-shaped valley is evidence that an area was once covered by a glacier. U-shaped valleys are formed by the erosion of a glacier as it moves down a slope, carving out a wide, flat-bottomed valley with steep sides. This distinct shape is different from the V-shaped valleys formed by rivers, which have a narrow, V-shaped bottom and less steep sides. Therefore, the presence of a U-shaped valley indicates that glaciers were present in the area in the past.

When waves erode the soft rock along the base of a steep coast, it gradually removes the material, creating a wave cut terrace. This landform is formed when the waves undercut the base of the coast, causing the overlying rock to collapse. Over time, this process repeats, resulting in a step-like formation along the coast. The wave cut terrace is typically flat and can extend for long distances parallel to the shoreline.