Science Topics

8.1 Contact Forces Why do things sometimes get damaged when they hit each other?

Students investigate causes of motion, and develop the idea that objects that collide can push on one another while they are in contact. Students connect the changes in the kinetic energy of an object to the energy being transferred to and from the object due to forces, and determine that the kinetic energy of an object is based on the two factors of mass and speed.

Forensics mini-unit Explore the careers involved in Forensic Science by training to solve a case.

8.2 Sound Waves How can sound make something move?

Students investigate how the frequency and amplitude of a sound wave can explain other macroscopic phenomena (loudness and pitch of a sound). Students explain at the molecular level how the deformation of materials results in oscillations that lead to the propagation of collisions of particles across a medium, and how the amplitude of the vibration is related to the energy of the wave.

8.3 Forces and Distances How can a magnet move another object without touching it?

Students explain how at-a-distance forces transfer energy between interacting objects in a system as the objects change position. This involves developing the idea of potential energy stored in systems of objects (e.g., magnets) and the transfer of this potential energy to the movement of objects depending on the objects’ position and orientation to each other.

8.4 Earth in Space Why do we see patterns in the sky and what else is out there that we cannot see?

Students investigate force and motion of objects in space, and how forces that act in a direction perpendicular to the motion of the object can lead to circular patterns of motion (an orbit). Students develop a model using gravity to explain patterns of motion of the earth, sun, moon, other planets and their moons, stars in our galaxy, and other galaxies. Students also investigate differences in the composition and surface features (crust, atmosphere, volcanoes) of planets in the solar system.

8.5 Genetics Why are living things different from one another?

Students investigate patterns in inheritance data to develop a model for how heredity information is encoded in genes on chromosomes, how these molecules affect traits through production of proteins, and how these molecules provide a mechanism for passing traits across generations. Students use their models to explain how variation arises in sexual reproduction and how patterns in heredity occur. Students models and use the model to explain how variations in genetic information can affect traits through production of proteins.

8.6 Natural Selection and Common Ancestry How could things living today be connected to those that lived long ago?

Students develop a model of natural selection that explains how trait distributions in populations shift over time. Students explore how differences between individuals and species' characteristics and behaviors enhance their fitness and how environmental changes can lead to shifts in trait distributions in a population over time. Students build on this model to investigate evidence from anatomical similarities and differences between organisms living today and organisms in the fossil record, and patterns in the traits of embryos from different species that are alive today, to extend a natural selection model to explain speciation.