About 3DL

Core Ideas

Disciplinary core ideas represent major themes of a particular scientific field. The core ideas defined in the 3DL4US projects are the product of discussions among experts in biology, chemistry, and physics.


  1. Chemical and Physical Basis of Life: Life processes are the result of regulated chemical and physical interactions and reactions governed by the laws of physics.
  2. Matter and Energy: Free energy and matter are used in regulated processes that establish order, support growth and development, and control dynamic homeostasis.
  3. Cellular Basis of Life: Cells are the fundamental units of all living things.
  4. Systems: Ecosystems, organisms, tissues, and cells act as systems.
  5. Structure and Function: The functions and properties of ecosystems, organisms, tissues, cells, and biological molecules are determined by their structures.
  6. Information Flow, Exchange, and Storage: Hereditary information is stored, used, and replicated.
  7. Evolution: Evolution drives the diversity and unity of life.


  1. Electrostatic and Bonding Interactions: Attractive and repulsive electrostatic forces govern noncovalent and bonding (covalent and ionic) interactions between atoms and molecules. The strength of these forces depends on the magnitude of the charges involved and the distances between them.
  2. Atomic/Molecular Structure and Properties: The macroscopic physical and chemical properties of a substance are determined by the three-dimensional structure, the distribution of electron density, and the nature and extent of the noncovalent interactions between particles.
  3. Energy: Energy changes are either the cause or the consequence of change in chemical systems, which can be considered on different scales and can be accounted for by conservation of the total energy of the system of interest and the surroundings.
  4. Change and Stability in Chemical Systems: Energy and entropy changes, the rates of competing processes, and the balance between opposing forces govern the fate of chemical systems.


  1. Interactions Can Cause Changes in Motion: Changes in an object’s motion are the result of interactions between it and one or more other objects. Multiple interactions between an object and its surroundings can result in a predictable change in motion.
  2. Energy is Conserved: Energy comes in many forms and can be transformed from one form to another within a given system or transferred between systems.
  3. Exchanges of Energy increase Total Entropy: Multiparticle systems tend toward states that are more statistically likely to occur. At a macroscopic scale, this can be described by concepts such as entropy, temperature, and pressure.
  4. Interactions are Mediated by Fields: Fields are generated by charges/masses. Fields affect charges/masses. In circuits, fields induce currents.
  5. Energy, Momentum, Angular Momentum, and Information can be Transported without a Net Transfer of Matter: Mechanical waves move through matter. Electromagnetic waves can move through vacuum or matter. Properties of waves can be used to parameterize the information or amount of energy, momentum, or angular momentum is transported.

Scientific Practices

The 8 Scientific Practices as defined by The FrameworkScientific practices are skills used by expert scientists to make sense of phenomena. They can also be thought of as the disaggregated components of “inquiry”. The eight scientific (and engineering) practices as defined by A Framework for K-12 Science Education are shown below.

  1. Asking questions (for scientists) and defining problems (for engineers)
  2. Developing & using models
  3. Planning & carrying out investigations
  4. Analyzing & interpreting data
  5. Using math & computational thinking
  6. Constructing explanations (for scientists) and designing solutions (for engineers)
  7. Engaging in argument from evidence
  8. Obtaining, evaluating, and communicating information

Crosscutting Concepts