Science Grade 8 Pre-Requisite Standards
Standard 10

Domain

Grade 8 Pro-Core Standard
(State Standard)

Related Prior Grade Standards

All language for Ohio’s Learning Standards in Science. Only the relevant sections of the standard and Content Elaborations are referenced.

Earth and Space Science

1
8.ESS.1

The composition and properties of Earth’s interior are identified by the behavior of seismic waves.

7.PS.4: Waves can be described by their speed, wavelength, amplitude and frequency. Vibrations cause wave- like disturbances that transfer energy from one place to another. Mechanical waves require a material (medium) in which to travel. The medium moves temporarily as the energy passes through it but returns to its original undisturbed position. Mechanical waves are classified as transverse or longitudinal (compressional) depending on the direction of movement of the medium. A wave travels at a constant speed through a particular material as long as it is uniform (e.g., for water waves, having the same depth). The speed of the wave depends on the nature of the material (e.g., sound waves travel faster through most solids than gases).

Gravitational potential energy is associated with the mass of an object and its height above a reference point (e.g., above ground level, above floor level). A change in the height of an object is evidence that the gravitational potential energy has changed.

Heat is the transfer of energy from a warmer object to a cooler one. Thermal energy can be transferred when moving atoms collide. This energy transfer is conduction. Thermal energy can also be transferred by means of thermal currents in air, water or other fluids. As fluids are heated, they expand, decreasing the density. Cooler material with a greater density sinks while warmer material with less density rises, causing currents that transfer energy. This energy transfer is convection.

6.PS.1. Equal volumes of different substances usually have different masses. Some materials, like lead or gold, have a lot of mass in a relatively small space. Other materials, like packing peanuts and air, have a small mass in a relatively large amount of space. This concept of comparing substances by the amount of mass the substance has in a given volume is known as density.

5.PS.2: As light reaches a new material, it can be absorbed, refracted, reflected or can continue to travel through the new material; one of these interactions may occur or many may occur simultaneously, depending on the material. When light passes from one material to another, it is often refracted at the boundary between the two materials and travels in a new direction through the new material (medium).

2
8.ESS.2

Earth’s lithosphere consists of major and minor tectonic plates that move relative to each other.

7.PS.4: Thermal energy can be transferred by means of thermal currents in air, water or other fluids. As fluids are heated, they expand, decreasing the density. Cooler material with a greater density sinks while warmer material with less density rises, causing currents that transfer energy. This energy transfer is convection.

4.ESS.1: Catastrophic events such as volcanoes and earthquakes can create landforms. Beginning to recognize common landforms or features are important ways to understand the formation of landforms and features. Common landforms and features include mountains/mountain ranges, volcanoes and islands. Connecting the processes that occur to the resulting landform, feature or characteristic is emphasized.

3
8.ESS.3

A combination of constructive and destructive geologic processes formed Earth’s surface.

4.ESS.1: Earth’s surface can change due to erosion and deposition of soil, rock or sediment.

Catastrophic events such as flooding, volcanoes and earthquakes can create landforms. There are many different processes that continually build up or tear down the surface of Earth. These processes include erosion, deposition, volcanic activity, earthquakes, glacial movement and weathering. Common landforms and features include streams, deltas, floodplains, hills, mountains/mountain ranges, valleys, sinkholes, caves, canyons, glacial features, dunes, springs, volcanoes and islands.

4.ESS.2: The surface of Earth changes due to weathering. Rocks change shape, size and/or form due to water or glacial movement, freeze and thaw, wind, plant growth, acid rain, pollution and catastrophic events such as earthquakes, flooding, and volcanic activity.

4.ESS.3: The surface of Earth changes due to erosion and deposition. Erosion is a process that transports rock, soil or sediment to a different location. Gravity plays an important role in understanding erosion, especially catastrophic events like mass movement (e.g., mudslides, avalanches, landslides) or flooding.

Erosion is a “destructive” process and deposition is a “constructive” process. Erosion and deposition directly contribute to formation of landforms and features.

4
8.ESS.4

Evidence of the dynamic changes of Earth’s surface through time is found in the geologic record.

6.ESS.3: Igneous, metamorphic and sedimentary rocks form in different ways. Magma or lava cools and crystallizes to form igneous rocks. Heat and pressure applied to existing rock forms metamorphic rocks. Sedimentary rock forms as existing rock weathers chemically and/or physically and the weathered material is compressed and then lithifies. Each rock type can provide information about the environment in which it was formed.

Rocks and minerals in rocks form in specific types of environments. The rock cycle can be used for a general explanation of the conditions required for igneous, metamorphic and sedimentary rocks to form.

Physical Science

5
8.PS.1

Objects can experience a force due to an external field such as magnetic, electrostatic, or gravitational fields.

5.PS.1: A force is described by its strength and the direction that it pushes or pulls an object.

4.PS.2: When a wire conducts electricity, the wire has magnetic properties and can push and/or pull magnets.

2.PS.1: Some forces act without touching, such as using a magnet to move an object or objects falling to the ground. … forces act when objects are not in contact with each other (e.g., magnetic, gravitational, electrical).

Earth’s gravity pulls any object toward it, without touching the object. Static electricity also can pull or push objects without touching the object. Magnets can pull some objects to them (attraction) or push objects away from them (repulsion).

6
8.PS.2

Forces can act to change the motion of objects.

5.PS.1: The amount of change in movement of an object is based on the mass of the object and the amount of force exerted.

Any change in speed or direction of an object requires a force and is affected by the mass of the object and the amount of force applied.

The motion of an object can change by speeding up, slowing down or changing direction. Forces cause changes in motion. If a force is applied in the direction of an object’s motion, the speed will increase. If a force is applied in the direction opposite an object’s motion, the speed will decrease.

The greater the force acting on an object, the greater the change in motion. The greater the mass of an object, the less influence a force will have on its motion. If no force acts on an object (or the forces are balanced), the object does not change its motion and moves at constant speed in a given direction. If an object is not moving and no force acts on it (or the forces are balanced), the object will remain at rest.

A force is described by its strength and the direction that it pushes or pulls an object. More than one force can act on an object at a time. At this grade level, only consider two forces acting on an object either horizontally or vertically. When two forces act on an object, their combined effect influences the motion of that object. The effect forces have on an object depends not only on the forces’ strengths, but also on their directions. If the forces have equal strengths, but act in opposite directions, the object’s motion will not change, and the forces are considered balanced. A stationary object subject to balanced forces will remain stationary. A moving object subject to balanced forces will continue moving in the same direction at the same speed. Unbalanced forces will cause change in the motion of an object. A stationary object subject to unbalanced forces will move in the direction of the larger force. Inquiry activities should be used to develop student understanding of the effects of forces on the motion of objects.

Movement is a change in position. Speed is a measurement of how fast or slow this change takes place. In the same amount of time, a faster object moves a greater distance than a slower object. Speed is calculated by dividing distance traveled by elapsed time. An object that moves with constant speed travels the same distance in each successive unit of time. When an object is speeding up, the distance it travels increases with each successive unit of time.

2.PS.1: Forces change the motion of an object.

Motion can increase, change direction or stop depending on the force applied.

The change in motion of an object is related to the size of the force.

Forces are needed to change the movement of an object by speeding up, slowing down, stopping or changing direction. Some forces act when an object is in contact with another object (e.g., physically pushing or pulling). Other forces act when objects are not in contact with each other (e.g., magnetic, gravitational, electrical).

For a particular object, larger forces cause larger changes in motion. A strong kick to a rock is able to cause more change in motion than a weak kick to the same rock.

Life Science

7
8.LS.1

Diversity of species, a result of variation of traits, occurs through the process of evolution and extinction over many generations. The fossil records provide evidence that changes have occurred in number and types of species.

7.LS.2: Ecosystems are dynamic in nature; the number and types of species fluctuate over time. Disruptions, deliberate or inadvertent, to the physical (abiotic) or biological (biotic) components of an ecosystem impact the composition of an ecosystem.

4.LS.1: Changes in an organism’s environment are sometimes beneficial to its survival and sometimes harmful.

When the environment changes, some plants and animals survive and reproduce and others die or move to new locations.

Ohio has experienced various climate patterns. Glaciers covered parts of Ohio and other parts of Ohio were submerged with water as indicated by Ohio’s fossil record. Major changes, both natural and human caused, over a short period of time can have significant impacts on ecosystems and populations of plants and animals. The changes that occur in the plant and animal populations can impact access to resources for the remaining organisms, which may result in migration or death.

The relationships between current and past ecosystems, the changes that have occurred over time in those ecosystems, and the species that lived there are explored.

4.LS.2: Fossils can be compared to one another and to present-day organisms according to their similarities and differences.

Most species that have lived on Earth are extinct.

Fossils provide a point of comparison between the types of organisms that lived long ago and those existing today.

Fossils provide evidence that many plant and animal species are extinct and other species have changed over time. The types of fossils that are present provide evidence about the nature of an ecosystem at that time. As an ecosystem changed, so did the types of organisms that could survive in that ecosystem.

3.LS.2: Individuals of the same kind of organism differ in their inherited traits. These differences give some individuals an advantage in surviving and/or reproducing.

Plants and animals have certain physical or behavioral characteristics that influence their chances of surviving in particular environments.

There may be variations in the traits that are passed down that increase the ability of organisms to survive and reproduce. Some variations in traits that are passed down may reduce the ability of organisms to survive and reproduce. Some variations in traits that are passed down may have no appreciable effect on the ability of organisms to survive and reproduce. Variations in physical features among animals and plants can help them survive in different environmental conditions. Variations in color, size, weight, etc., can be observed as the organism develops.

Plants and animals that survive and reproduce pass their features (traits) on to their offspring and future generations. Some grade-appropriate organisms to study are plants (e.g., radishes, beans) and animals (e.g., butterflies, moths, beetles, brine shrimp).

2.LS.2: All organisms alive today result from their ancestors, some of which may be extinct. Not all kinds of organisms that lived in the past are represented by living organisms today.

Some kinds of organisms become extinct when their basic needs are no longer met or the environment changes.

Fossils are preserved physical traces of past living things (e.g., shells, bones, leaves, tracks, imprints, eggs, scat). Some fossils look similar to plants and animals that are alive today, while others are very different from anything alive today.

Extinction refers to the disappearance of the last individual of a kind of organism. Extinction generally occurs as a result of changed conditions where the basic needs are not met. Some kinds of living things that once lived on Earth have completely disappeared (e.g., saber-tooth cat, trilobite, mastodon). Plants and animals alive today resemble organisms that once lived on Earth (e.g., ferns, sharks).

8
8.LS.2

Every organism alive today comes from a long line of ancestors who reproduced successfully every generation.

6.LS.2: All cells come from pre-existing cells.

Cells repeatedly divide resulting in more cells and growth and repair in multicellular organisms.

Modern Cell Theory states that cells come from pre-existing cells. Individual organisms do not live forever. Therefore, reproduction is necessary for the continuation of every species. Traits are passed on to the next generation through reproduction. Single-celled organisms reproduce by processes such as mitosis, budding and binary fission.

In this grade, mitosis is explored. In multicellular organisms, mitosis allows cells to multiply for the purpose of growth and repair. All cells contain genetic materials. At this grade level, the genetic material is described as chromosomes. Chromosomes are described as structures in cells that contain genetic material. The chemicals and chemical processes associated with chromosomes are reserved for high school biology. Microscopes, micrographs, models and illustrations can be used to observe cells from different organisms in the process of dividing. It is not appropriate to learn the names of the stages of mitosis. The focus is on observing cells dividing as evidence that cells come from pre-existing cells and genetic material is transmitted from parent cell to daughter cells.

The misconception of spontaneous generation can be included in discussions on this topic. The experiments of Redi and Pasteur can be used to explain how evidence can lead to new knowledge, better explanations and spur new technology.

9
8.LS.3

The characteristics of an organism are a result of inherited traits received from parent(s).

3.LS.1: Offspring resemble their parents and each other.

Individual organisms inherit many traits from their parents indicating a reliable way to transfer information from one generation to the next.

Organisms are similar to their parents in appearance and behavior but still show some variation. Although the immature stages of some living things may not resemble the parents, once the offspring matures, it will resemble the parent. At this grade level, care should be taken to avoid introducing the misconception that the individual organism has a way to select the traits that are passed to the next generation. As part of the study of the life cycle of organisms, the physical appearance of the adults will be compared to the offspring (e.g., compare butterflies to determine if offspring look exactly like the parents).

A considerable amount of animal behavior is directly related to getting materials necessary for survival (e.g., food, shelter) from the environment. The focus at this grade level is on examples of animals engaging in instinctual behaviors. Some organisms have behavioral traits in response to environmental stimuli (e.g., a plant stem bending toward the light).