Subjects › Middle School Physical Science
Middle School Physical Science: matter, forces, energy, and waves, explained by talking it
This course covers the full span of NGSS middle school physical science: the particle model of matter, evidence of chemical reactions and conservation of mass, states of matter and thermal energy, synthetic materials, Newton's laws, gravity, electric and magnetic forces and fields, kinetic and potential energy, energy transfer, and waves and information encoding. Engineering design and the practice of building and testing models run throughout, the same way they do in an NGSS classroom.
Instead of reading explanations and answering multiple-choice questions, the student talks through each idea with a tutor that asks questions. A lesson might start with 'what happens to the particles in water when you heat it?' rather than a paragraph defining thermal energy. The tutor notices when an answer is partly right, builds on it, and checks weeks later that an idea like conservation of mass still holds up when it shows up again in a new context, like a chemical hand warmer.
Who it is for
- Middle schoolers taking a physical science class that follows NGSS standards (MS-PS1 to MS-PS4, MS-ETS1)
- Students who want to talk through ideas like Newton's laws or conservation of mass instead of memorizing definitions
- Parents looking for a supplement that matches what's taught in class, not a different curriculum
- Teachers wanting extra one-on-one practice for students who need to explain their reasoning, not just pick an answer
- Students preparing for a unit test on forces, energy, matter, or waves who want to check they can explain, not just recall
What you will be able to do
- Explain how atoms rearrange in a chemical reaction and show that mass is conserved
- Use Newton's laws to predict what happens when forces on an object are unbalanced
- Explain gravitational, electric, and magnetic forces in terms of fields acting at a distance
- Calculate how kinetic energy changes with mass and speed, and track energy transfer in a system
- Describe how thermal energy moves by conduction, convection, and radiation, and design for it
- Explain how waves carry energy and information, and compare analog to digital encoding
A taste of a lesson on Conservation of atoms and mass in reactions
The tutor asks, you answer, and it works from what you actually said. No videos to sit through.
The 22 topics in Middle School Physical Science
Each topic builds on the ones before it. The tutor checks what you already know and starts there.
Engineering design process and criteria/constraints
Introduce the engineering design cycle: defining a problem, identifying criteria (what success looks like) and constraints (limits such as cost, materials, safety, environmental or human impact). Teach how to write precise, testable criteria and constraints, including constraints drawn from relevant scientific principles and potential impacts on people and the natural environment, and how to evaluate competing solutions with a systematic decision matrix or weighted scoring. Students should be able to take a vague problem and write measurable criteria and constraints, then compare two designs against them.
Modeling, testing, and iterating designs
Teach how to build a model or prototype that generates data, run controlled tests, record results, analyze test data across several design solutions to find similarities, differences, and the best characteristics of each, then combine them into an improved solution. Emphasize iterative cycles of test, modify, retest toward an optimal design.
Builds on Engineering design process and criteria/constraints
Particle model of matter and atomic composition
Teach that all matter is made of atoms; atoms of different elements differ in the number of protons, and atoms bond to form molecules (e.g., H2O, CO2, O2) and extended structures (e.g., salt crystal lattice, diamond, graphite). Students build and interpret models showing which atoms and how many are in simple molecules and repeating structures, and describe what each model shows and fails to show.
Properties of substances and evidence of chemical reactions
Teach physical versus chemical properties and changes. Key evidence of a chemical reaction includes new substances with different properties, color change, gas production, temperature change, precipitate formation, and light. Students analyze before-and-after data tables and graphs to decide whether a reaction occurred and justify the claim with specific evidence.
Builds on Particle model of matter and atomic composition
Conservation of atoms and mass in reactions
Teach that in a chemical reaction atoms are rearranged, not created or destroyed, so the total number of each type of atom and total mass stay the same. Students build molecular models of reactants and products (e.g., hydrogen and oxygen forming water), count atoms on each side, and explain why a closed-container mass measurement stays constant while an open container may appear to lose mass when a gas escapes.
Builds on Particle model of matter and atomic composition, Properties of substances and evidence of chemical reactions
Thermal energy, particle motion, and states of matter
Teach that temperature reflects average kinetic energy of particles and that adding thermal energy increases particle motion; during a phase change (melting, boiling) added energy changes potential energy of particle arrangement while temperature stays constant. Students build and use a particle model that predicts and describes how particle motion, temperature, and state change when thermal energy is added or removed, reading heating/cooling curves for a pure substance.
Builds on Particle model of matter and atomic composition
Synthetic materials from natural resources and their societal impact
Teach how synthetic materials such as plastics, nylon, rubber vulcanization products, and synthetic fibers are made from natural resources (petroleum, natural gas, plant cellulose, minerals) through chemical processes. Students gather and evaluate information on benefits and impacts on society and environment, such as recycling, pollution, and cost, and make a reasoned claim supported by sources.
Builds on Properties of substances and evidence of chemical reactions
Forces and Newton's first and third laws
Teach that a force is a push or pull measured in newtons, that forces are interactions between objects, and that net force determines change in motion. Cover Newton's first law (inertia) and Newton's third law (equal and opposite forces on two interacting objects). Students apply the third law to analyze collisions and design simple solutions such as crash protection or padding that changes collision outcomes.
Builds on Engineering design process and criteria/constraints
Net force, mass, and change in motion (Newton's second law)
Teach that the change in an object's motion depends on the sum (net) of forces and on the object's mass; more net force gives greater change in motion and more mass gives less change for the same force. Students plan an investigation (e.g., carts with varied masses and pulls, measuring speed change with timers) to produce evidence for this relationship, controlling variables and identifying confounding factors.
Builds on Modeling, testing, and iterating designs, Forces and Newton's first and third laws
Gravitational interaction and mass
Teach that gravity is always attractive between any two objects with mass, that the force increases with the masses of the objects and decreases with distance, and that Earth's gravity on objects near its surface produces weight. Students construct evidence-based arguments (e.g., comparing falling objects, planetary examples, the Moon and Earth) that gravitational interactions are attractive and depend on mass.
Builds on Forces and Newton's first and third laws
Electric and magnetic forces and what affects their strength
Teach that electric forces act between charged objects (like charges repel, opposite attract) and magnetic forces act between magnets and magnetic materials; both act at a distance. Factors affecting strength include charge amount and distance for electric forces, and magnet strength, distance, and orientation for magnets, with electromagnets' strength depending on current and number of coils. Students ask questions about data sets to identify these factors.
Builds on Forces and Newton's first and third laws
Force fields between non-contacting objects
Teach that gravitational, electric, and magnetic forces act across space through fields: a field exists around a mass, charge, or magnet and exerts force on other objects in it even without contact. Students conduct an investigation (e.g., iron filings around a magnet, a charged object near a light foil, a compass near a current or magnet) and evaluate the experimental design, including controls and whether observations truly show a field.
Builds on Gravitational interaction and mass, Electric and magnetic forces and what affects their strength
Kinetic energy and its dependence on mass and speed
Teach that kinetic energy is energy of motion, depends on mass and speed, and increases more strongly with speed (proportional to speed squared). Students construct and interpret graphs of kinetic energy versus mass and versus speed from data, identifying the relationships (linear with mass, nonlinear with speed).
Builds on Net force, mass, and change in motion (Newton's second law)
Potential energy from arrangement of interacting objects
Teach that stored energy depends on the arrangement of objects that interact at a distance: gravitational potential energy depends on mass and height, elastic potential energy on stretch or compression, and electric and magnetic potential energy on relative positions. Students develop a model showing that changing the arrangement changes the stored energy in the system, and track energy transformations between kinetic and potential forms in examples like roller coasters or pendulums.
Builds on Gravitational interaction and mass, Force fields between non-contacting objects, Kinetic energy and its dependence on mass and speed
Energy transfer during changes in kinetic energy
Teach that when an object's kinetic energy changes, energy is transferred to or from it, typically through work done by a force, which is the force times distance in the direction of the force. Students construct and present an argument, supported by evidence, that energy transfer accompanies every change in kinetic energy (e.g., braking a car, a ball hit by a bat).
Builds on Forces and Newton's first and third laws, Net force, mass, and change in motion (Newton's second law), Kinetic energy and its dependence on mass and speed
Thermal energy transfer: conduction, convection, radiation and designing for it
Teach that thermal energy moves from hot to cold by conduction (contact), convection (fluid movement), and radiation (electromagnetic waves), and that materials differ in conductivity and insulating ability. Students apply these principles to design, build, and test a device (such as an insulated cup or a heat sink) that either minimizes or maximizes thermal energy transfer, using temperature measurements.
Builds on Modeling, testing, and iterating designs, Thermal energy, particle motion, and states of matter
Energy, mass, and material in temperature change
Teach that the temperature change of a sample depends on the energy transferred into it, its mass, and the type of matter (specific heat differs among materials, e.g., water heats more slowly than sand). Students plan a controlled investigation varying one factor at a time, measuring temperature change, and determine the relationships among energy transferred, matter type, mass, and temperature change.
Builds on Thermal energy, particle motion, and states of matter, Kinetic energy and its dependence on mass and speed, Energy transfer during changes in kinetic energy
Exothermic and endothermic chemical processes and thermal devices
Teach that chemical reactions absorb or release thermal energy (endothermic: cold packs, photosynthesis; exothermic: hand warmers, combustion), explained by energy stored in chemical bonds. Students then undertake a design project to construct, test, and modify a device that releases or absorbs thermal energy through a chemical process, measuring temperature change and iterating the design.
Builds on Engineering design process and criteria/constraints, Modeling, testing, and iterating designs, Particle model of matter and atomic composition, Properties of substances and evidence of chemical reactions, Thermal energy transfer: conduction, convection, radiation and designing for it, Energy, mass, and material in temperature change
Wave properties: amplitude, wavelength, frequency, and energy
Teach that waves transfer energy without transferring matter, with key properties of wavelength, frequency, amplitude, and speed. Students use simple mathematical representations (e.g., wave diagrams, proportional reasoning) to show that a wave's amplitude is related to the energy it carries, with larger amplitude carrying more energy.
Builds on Kinetic energy and its dependence on mass and speed, Potential energy from arrangement of interacting objects
Sound and light as waves and the electromagnetic spectrum
Teach that sound is a mechanical wave that needs a medium and light is an electromagnetic wave that can travel through a vacuum; the electromagnetic spectrum orders waves (radio, microwave, infrared, visible, ultraviolet, X-ray, gamma) by wavelength and frequency, with visible light a small band. Explain how waves carry information: sound and light signals can be used to send messages (e.g., speech, fiber optics, radio), and the same wave properties (amplitude, frequency, wavelength) can be varied to encode information.
Builds on Electric and magnetic forces and what affects their strength, Wave properties: amplitude, wavelength, frequency, and energy
Reflection, absorption, and transmission of waves
Teach that when a wave meets a boundary between materials, it may be reflected, absorbed, or transmitted (or some combination), depending on the material and wave type. Examples include light reflecting from mirrors, absorbed by dark cloth, transmitted through glass; sound echoes and insulation. Students develop and use a model to describe these outcomes across materials.
Builds on Wave properties: amplitude, wavelength, frequency, and energy, Sound and light as waves and the electromagnetic spectrum
Digital versus analog signal encoding and transmission
Teach that analog signals vary continuously and accumulate noise that degrades information, while digital signals encode information as discrete values (binary 0s and 1s) that can be regenerated and checked, making them more reliable over distance. Students integrate qualitative information from multiple sources to build an argument for why digitized signals are more reliable for encoding and transmitting information.
Builds on Sound and light as waves and the electromagnetic spectrum, Reflection, absorption, and transmission of waves
Practice questions in Middle School Physical Science
A few of the kinds of questions you will work through, with answers.
What makes an atom of oxygen different from an atom of carbon?
See the answer
The number of protons in the nucleus
Each element is defined by its number of protons; oxygen has 8, carbon has 6.
You mix two clear liquids and the mixture turns cloudy and warms up. Is this more likely a physical or chemical change, and why?
See the answer
Chemical change
A new substance (the cloudy precipitate) formed and a temperature change occurred, both signs of a chemical reaction.
A book sits still on a table. Why doesn't gravity pull it through the table?
See the answer
The table pushes up on the book with an equal and opposite force
The upward normal force from the table balances gravity, giving a net force of zero, so the book stays at rest (Newton's first and third laws).
Two carts are pushed with the same force. Cart A has twice the mass of Cart B. Which cart speeds up more, and by how much compared to the other?
See the answer
Cart B speeds up twice as much as Cart A
For the same net force, a smaller mass produces a greater change in motion; doubling the mass halves the change for the same force.
If a car's speed doubles while its mass stays the same, what happens to its kinetic energy?
See the answer
It becomes four times as large
Kinetic energy increases with the square of speed, so doubling speed quadruples kinetic energy.
Why can a digital audio signal be copied many times with no loss in sound quality, while an analog tape recording gets worse each time it's copied?
See the answer
Digital signals use discrete values that can be regenerated exactly, while analog signals vary continuously and pick up noise each time they're copied
Digital 0s and 1s can be detected and rebuilt cleanly even with some noise, but analog signals have no such discrete reference, so noise accumulates with each copy.
Questions about this subject
Does this follow the NGSS standards my child's school uses?
Yes, the topics map to NGSS middle school physical science: MS-PS1 (matter), MS-PS2 (forces), MS-PS3 (energy), MS-PS4 (waves and information), and MS-ETS1 (engineering design), covered in that order.
Does this include balancing chemical equations or circuits?
No. This course stops before high school chemistry topics like stoichiometry and formal equation balancing, and before formal electric circuits, vectors, and quantitative kinematics equations, which belong to high school physical science.
My child hasn't done algebra yet. Will that be a problem?
No algebra is required beyond simple proportional reasoning, such as recognizing that doubling speed roughly quadruples kinetic energy. The course assumes grade 5 science foundations and basic arithmetic.
How does the tutor handle a student who gives a wrong or incomplete answer?
The tutor responds to what the student actually said, confirms what's correct, and asks a follow-up question that leads them toward the gap, rather than just supplying the right answer.
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