Looking for free content that’s aligned to your standards? You’ve come to the right place!
Get Free 8th Grade Science Content
Khan Academy is a nonprofit with thousands of free videos, articles, and practice questions for just about every standard.
No ads, no subscriptions – just 100% free, forever.
ESS Earth and Space Science
- Physical Earth
- 8.ESS.1 The composition and properties of Earth’s interior are identified by the behavior of seismic waves.
- 8.ESS.1.a The refraction and reflection of seismic waves as they move through one type of material to another is used to differentiate the layers of Earth’s interior. Earth has a core, a mantle, and a crust. Impacts during planetary formation generated heat.
- 8.ESS.1.b These impacts converted gravitational potential energy to heat. Earth’s core is also able to generate its own thermal energy because of decaying atoms. This continuously releases thermal energy. Thermal energy generated from Earth’s core drives convection currents in the asthenosphere.
- 8.ESS.2 Earth’s lithosphere consists of major and minor tectonic plates that move relative to each other.
- 8.ESS.2.a Historical data and observations such as fossil distribution, paleomagnetism, continental drift and sea-floor spreading contributed to the theory of plate tectonics. The rigid tectonic plates move with the molten rock and magma beneath them in the upper mantle.
- 8.ESS.2.b Convection currents in the asthenosphere cause movements of the lithospheric plates. The energy that forms convection currents comes from deep within the Earth.
- 8.ESS.2.c There are three main types of plate boundaries: divergent, convergent and transform. Each type of boundary results in specific motion and causes events (such as earthquakes or volcanic activity) or features (such as mountains or trenches) that are indicative of the type of boundary.
- 8.ESS.3 A combination of constructive and destructive geologic processes formed Earth’s surface.
- 8.ESS.3.a Earth’s surface is formed from a variety of different geologic processes, including but not limited to plate tectonics.
- 8.ESS.4 Evidence of the dynamic changes of Earth’s surface through time is found in the geologic record.
- 8.ESS.4.a Earth is approximately 4.6 billion years old. Earth history is based on observations of the geologic record and the understanding that processes observed at present day are similar to those that occurred in the past (uniformitarianism). There are different methods to determine relative and absolute age of some rock layers in the geologic record. Within a sequence of undisturbed sedimentary rocks, the oldest rocks are at the bottom (superposition). The geologic record can help identify past environmental and climate conditions.
- 8.ESS.1 The composition and properties of Earth’s interior are identified by the behavior of seismic waves.
PS Physical Science
- Forces and Motion
- 8.PS.1 Objects can experience a force due to an external field such as magnetic, electrostatic, or gravitational fields.
- 8.PS.1.a Magnetic, electrical and gravitational forces can act at a distance.
- 8.PS.2 Forces can act to change the motion of objects.
- 8.PS.2.a The motion of an object is always measured with respect to a reference point.
- 8.PS.2.b Forces can be added. The new force on an object is the sum of all of the forces acting on the object.
- 8.PS.2.c If there is a nonzero net force acting on an object, its speed and/or direction will change.
- 8.PS.2.d Kinetic friction and drag are forces that act in a direction opposite the relative motion of objects.
- 8.PS.1 Objects can experience a force due to an external field such as magnetic, electrostatic, or gravitational fields.
LS Life Science
- Species and Reproduction
- 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.
- 8.LS.1.a Fossils provide important evidence of how life and environmental conditions have changed.
- 8.LS.1.b Changes in environmental conditions can affect how beneficial a trait will be for the survival and reproductive success of an organism or an entire species.
- 8.LS.1.c Throughout Earth’s history, extinction of a species has occurred when the environment changes and the individual organisms of that species do not have the traits necessary to survive and reproduce in the changed environment. Most species (approximately 99 percent) that have lived on Earth are now extinct.
- 8.LS.2 Every organism alive today comes from a long line of ancestors who reproduced successfully every generation.
- 8.LS.2.a Reproduction is the transfer of genetic information from one generation to the next. It can occur with mixing of genes from two individuals (sexual reproduction). It can occur with the transfer of genes from one individual to the next generation (asexual reproduction). The ability to reproduce defines living things.
- 8.LS.3 The characteristics of an organism are a result of inherited traits received from parent(s).
- 8.LS.3.a Expression of all traits is determined by genes and environmental factors to varying degrees. Many genes influence more than one trait, and many traits are influenced by more than one gene.
- 8.LS.3.b During reproduction, genetic information (DNA) is transmitted between parent and offspring. In asexual reproduction, the lone parent contributes DNA to the offspring. In sexual reproduction, both parents contribute DNA to the offspring.
- 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.