6th grade Science CBA (earth)

elevation, relief, and slope

Topographic maps have contour lines, indicating the height of that area, when a contour line forms a v shape on a topographic map, that's a valley. When there is a line (usually blue) that goes through it, that's a river.

A depression is marked by closed loops of contour lines with little dashes called ticks that point to a lower elevation.

On a topographic map, there are contour loops that sometimes make closed loops, representing a hill. In the middle of the loops, there is a symbol, usually an X with the highest elevation on it.

(The elevation next to the symbol has t o be higher than the loop immediately around it, but lower than the elevation that the next contour line would be.

• Mechanical:
• Refrain From Pushing Angry Alligators
• Release of pressure, Freezing and thawing, Plants, Abrasion, Animal actions

• Chemical:
• What Can Penguins Argue Over?
• Water, C0², Plant acid, Acid Rain, Oxidation

The two factors of weathering are climate and the kind of rock. Climate is a factor because the warmer and wetter it is, the easier the rock is weathered because there is a lot of C0² in hot climates which weathers the rock, and the water also wears away the rock as opposed to a cold, dry climate. The reason the kind of rock is a factor of weathering because the more permeable a rock is, the more surface area there is to be weathered which makes the rock weather faster than less permeable rocks.

Erosion is consistantly working through water, erosion, gravity, and ice. Erosion is when these sediments get picked up by one or more of these forces and moved. When these sediments are put in an area, that is deposition, when this orccurs for a while, deposition can create landforms like hills and mountains. Together, these wear down and build up earth's surface.

Water!

One result of deposition along a stream is an oxbow lake. When there is a meander and deposition cuts the meander off from the stream/river, it forms an oxbow lake. The other result is an alluvial fan. An alluvial fan is a fan-shaped area of deposition found at the mouth of a stream, these are made when water carrying sediments slows down at a point and deposits the sediment. Eventually, the stream meanders around the deposition and continues to deposit and wear away sediment.

A fossil forms when an animal leaves a print, or dies, leaving it's bones. These get covered by sediment and get preserved by it. After millions of years, the fossil surfaces at the top. But for a print, the animal leaves a print and the print can get covered by sediment and surface, preserving the print. If sediments get pressed into the print and harden then resurface, it's called a cast. When sediments completely replace the atomical make up of something, it's called a petrified fossil. :D

:D

The fossil record shows what animals were alive in an area and when they were alive. The fossil record also shows the climate/status of the land (i.e. swamp, lava, ocean.)

The Law of Superpostion is a law that states that rock layers below other layers have to be older than the ones ontop of them, ergo, the layers ontop have to be younger.

Index fossils are the fossils of an organism that was around for a short period of time in a vast area. These are useful because they were around for a short period of time, so it's easy to know about how old the fossil is, so when it is found in a layer of rock, the rock can be dated.

The rock that the intrusion goes through is older than the intrusion because the layer had to be there for the intrusion to go through it.

minerals, decayed organic material, water, and air.

Kind of rock and climate

Topsoil, horizon A, B, C, and bedrock

• A is: Fertile, a lot of organisms, and not very rocky.
• B is: pretty fertile, some organisms, and pretty rocky.
• C is: Not too fertile, a couple organisms, and extremely rocky

• -Plant roots break apart rocks and help hold soil in place
• -Bacteria breaks down organisms and their wastes
• -Leaves, roots, and stems are a key part of humus
• -Animals like worms break up compacted soil, making it easier for plant roots to spreas and water to enter the soil
• -fungi lets out rootlike threads and releases chemicals that digest plant remains.
• -decomposers decompose

After the first atmosphere was lost, a second atmosphere formed around earth, and volcanic erruptions spewed out co^2, water vapor, and other gasses. Also, comets consisting of water and frozen gasses such as co² hit the earth. The CO² from the volcanoes and comets then got taken in by plants and turned into oxegyn which the plant produced [this is called photosynthesis.]

Pangea was a landform made up of all the continents. This reoccurs ever so often, so Pangea was the most recent one.

• Fun Fact:
• Before Pangea were Gondwala and Rodinia

The theory for the mass extinction of dinosaurs is that a giant item or asteroid hit the earth, killing all the animals in it's path. When the asteroid hit, it created such a giant plume that the sunlight was decreased for years making plants die, which inturn made herbivores die, ergo, making carnivored die.

The mass extinction of dinosaurs affected mammals by letting them thrive and evolve into what they are now.

The grologic time scale is a record of organism evolution and geologic events in earth's history, found through rocks.

Cenozoic is divided into quaternary and tertiary

Mesozoic is divided into cretaceous, jurassic, and triassic

Paleozoic is divided into Permian, Carboniferous, Devonian, Silurian, Ordovician, and Cambrian

Scientists determine the relative age of rocks by using the Law of Superposition that states that rock layers are older then the layers ontop of them are, ergo the ones ontop are younger. If there is a fault, then the scientists try to match layers then use the Law of Superposition. If there is an extrusion, then it is younger than the layers beneath it but older than the layers ontop of it because it's basically like a new layer being added down you you normally use relative dating. Intrusions are younger than the rocks they go through because the rocks they go through have to be there in order for the intrusion to exist. They tell the absolute age by doing radioactive dating, or by using index fossils.