Unit 2: How does a small spark trigger a huge explosion?

Investigation 1: What is happening when a spark occurs?

In this investigation, the class begins discussing and exploring energy. Students start by defining energy and gathering evidence to explain the differences between potential and kinetic energy. Readings in this investigation support students in conceptualizing what energy is, and how it can be thought of as an accounting system. The class collaboratively completes investigations and analyze data to explore energy transfer and energy conservation. Through these investigations, students collaboratively develop a model of energy that can be used to predict and explain observable phenomena and the macroscopic and sub-microscopic scales.

HS-PS3-2. Develop and use models to illustrate that energy at the macroscopic scale can be accounted for as a combination of energy associated with the motion of particles (objects) and energy associated with the relative positions of particles (objects).

Investigation 2: Where does the energy of a spark come from?

In this investigation, Students start by defining potential energy as energy that is stored in a system of interacting objects. Readings help students explore observable phenomena using their definitions of potential and kinetic energy. Student then explore the relationship between potential energy and fields in order to explain how the objects interact without touching. The class uses the evidence collected to evaluate factors that affect the amount of potential energy stored in a system.

HS-PS3-5. Develop and use a model of two objects interacting through electric or magnetic fields to illustrate the forces between objects and the changes in energy of the objects due to the interaction.

HS-PS3-4. Plan and conduct an investigation to provide evidence that the transfer of thermal energy when two components of different temperature are combined within a closed system results in a more uniform energy distribution among the components in the system (second law of thermodynamics).

Investigation 3: How can a small spark start a huge explosion?

This investigation focuses on how electric forces and energy are connected to molecules. Readings in this investigation support students in representing their ideas about atoms and molecules the way that scientists do in the field – helping them both develop and learn from scientific text. Students will explore various simulations to build their understanding of the relationships among electric forces, energy, and the relative distance of two atoms. They will also explain the energy transfers that occur when molecules form and break using the concept of conservation of energy (developed in previous investigations).

HS-PS1-4. Develop a model to illustrate that the release or absorption of energy from a chemical reaction system depends upon the changes in total bond energy.

Investigation 4: Where does all the energy in an explosion come from?

Through collaborative class discussions using evidence from previous investigations, students will characterize a chemical reaction as a process of rearrangement of atoms that results in the formation of a new substance. Readings in this investigation help students see where chemical reactions show up in their everyday lives, and connect those real-life experiences to what is going on in class. Students will track energy throughout a chemical reaction, and develop a written evidence-based explanation to answer the driving question “How can a small spark start a huge explosion?”

HS-PS1-4. Develop a model to illustrate that the release or absorption of energy from a chemical reaction system depends upon the changes in total bond energy.

HS-PS1-5. Apply scientific principles and evidence to provide an explanation about the effects of changing the temperature or concentration of the reacting particles on the rate at which a reaction occurs.