HS-PS3-2: Modeling Energy as Particle Motion or Energy in Fields
In plain English: HS-PS3-2 is the NGSS high school performance expectation that asks students to develop and use models showing that every form of energy at the everyday scale is either motion of particles or energy stored in fields. Thermal energy and sound are particle motion; energy of height, charged plates and stretched materials is stored in fields. It is usually taught in Physics, Chemistry or Physical Science.
Develop and use models to illustrate that energy at the macroscopic scale can be accounted for as either motions of particles or energy stored in fields.
Clarification Statement: Examples of phenomena at the macroscopic scale could include the conversion of kinetic energy to thermal energy, the energy stored due to position of an object above the earth, and the energy stored between two electrically-charged plates. Examples of models could include diagrams, drawings, descriptions, and computer simulations.
Next Generation Science Standards · Disciplinary Core Idea: Energy · Official standard
Students develop and use models to show that the energy of everyday objects can always be accounted for in one of two ways: as motion of particles, or as energy stored in fields. The kinetic energy of a rolling ball is the motion of all its particles moving together; thermal energy is their random motion; sound is their organized back-and-forth motion. Energy that depends on position, such as a lifted backpack, a pair of charged plates or a stretched spring, is stored in a gravitational, electric or magnetic field between the parts of a system. Students draw particle and field diagrams, run a simulation, analyze invented data and critique each other's models.
The NGSS Clarification Statement says: "Examples of phenomena at the macroscopic scale could include the conversion of kinetic energy to thermal energy, the energy stored due to position of an object above the earth, and the energy stored between two electrically-charged plates. Examples of models could include diagrams, drawings, descriptions, and computer simulations." HS-PS3-2 has no official Assessment Boundary. All data sets on this page are invented for teaching. Constants used: g = 9.8 m/s², Boltzmann constant k = 1.38 × 10⁻²³ J/K, ε0 = 8.85 × 10⁻¹² F/m, specific heat of water 4180 J/(kg·°C) and of steel 450 J/(kg·°C).
Learning Objectives
By the end of this lesson, students will be able to:
Classify a macroscopic form of energy as motion of particles or as energy stored in a field, and justify the choice
Draw a particle model that shows how kinetic energy of an object becomes thermal energy, the random motion of its particles
Draw a field model that shows why lifting an object or separating charged plates stores energy in the system, not in one object
Use a model with simple calculations (½mv², mgh, mcΔT, ½CV², (3/2)kT) to predict and explain energy changes
Critique a model for missing parts, such as a field with no source or a thermal change with no particle motion
Prior Knowledge Required
Students should already be comfortable with:
Particle motion, temperature and state change when thermal energy is added or removed MS-PS1-4
Potential energy changes when objects that interact at a distance are rearranged MS-PS3-2
Kinetic energy, gravitational energy and energy conservation in a system HS-PS3-1
Ask students to rub their palms together hard for ten seconds, then hold a book above their desk.
Warm-Up Prompt
"Your hands got warmer, and the book has energy because it is high up. For each one, draw what you think is happening that we cannot see. Is something moving, or is something stored? Where?"
Post the drawings. Students usually draw moving particles for the hands but have trouble saying where the book's energy is. Keep both drawings: the lesson gives the two answers.
Direct Instruction15-20 minutes
Two accounts of all macroscopic energy. (1) Motion of particles: kinetic energy of a whole object (all particles moving together), thermal energy (random motion of particles), sound (organized vibration of particles). (2) Energy stored in fields: gravitational energy (field between an object and Earth), electric energy (field between charges, such as charged plates), magnetic energy (field between magnets), and the energy of stretched or compressed materials and of chemical bonds (electric fields between atoms). Light is energy carried by electric and magnetic fields through space. Use Diagram 1 for particle motion and Diagram 2 for fields.
Kinetic energy to thermal energy (particle model)
A sealed bag holding 1.0 kg of steel shot is dropped 1.0 m onto the floor 50 times. Each time the bag stops without bouncing.
Result: Field energy released: 50 × (1.0)(9.8)(1.0) = 490 J. Model: the ordered motion of all the pellets falling together becomes random motion of their particles when the bag stops. If all of it stays in the shot, ΔT ≈ 490 ÷ (1.0 × 450) ≈ 1.1 °C at most.
Energy stored by position above Earth (field model)
A student lifts a 12 kg backpack onto a shelf 1.5 m above the floor.
Result: ΔE = mgh = (12)(9.8)(1.5) = 176.4 J. The energy is stored in the gravitational field of the Earth-backpack system; neither object has it alone, because the energy depends on the distance between them.
Energy stored between charged plates (field model)
A calculation, not a class demonstration: two metal plates, each 0.10 m × 0.10 m, sit 2.0 mm apart in air with 2000 V between them.
Result: E = V/d = 2000 ÷ 0.0020 = 1.0 × 10⁶ V/m, below the 3 × 10⁶ V/m at which air breaks down. C = ε0A/d = 4.4 × 10⁻¹¹ F, so U = ½CV² ≈ 8.9 × 10⁻⁵ J, stored in the field between the plates.
Thermal energy as particle speed (particle model)
Nitrogen in a sealed syringe is warmed from 300 K to 360 K.
Result: Average kinetic energy per molecule = (3/2)kT: 6.21 × 10⁻²¹ J at 300 K and 7.45 × 10⁻²¹ J at 360 K, 1.2 times larger. Typical molecular speed rises from about 517 m/s to about 566 m/s.
Stretched spring (field model at the atomic scale)
A spring with k = 200 N/m is stretched 0.10 m.
Result: U = ½kx² = ½(200)(0.10)² = 1.0 J. Stretching pulls the atoms slightly apart against the electric forces between them, so the energy is stored in the electric fields between atoms.
After each example, ask two questions: "Is this energy motion or storage?" and "If it is stored, which two things does the field connect?" Stress that a model is useful only if it predicts something: the particle model predicts that faster particles mean a higher temperature, and the field model predicts that pulling apart attracting objects takes work.
Guided Practice15 minutes
Pairs classify eight phenomena, then draw a quick model for any two of them. The last two columns are the teacher key.
Guided practice: classify and model eight phenomena
Phenomenon
Energy we notice
Particle motion or field?
Key for the teacher
A rolling bowling ball
Kinetic
Particle motion
All particles move together in one direction
A bowl of hot soup
Thermal
Particle motion
Random motion of water molecules
A book on a high shelf
Gravitational
Field
Field between the book and Earth
A charged capacitor
Electric
Field
Field between the charged plates
A stretched rubber band
Elastic
Field
Electric fields between molecules
Sound from a speaker
Sound
Particle motion
Air molecules vibrating back and forth together
Sunlight crossing space
Light
Field
Electric and magnetic fields carry it
Two magnets held apart while attracting
Magnetic
Field
Field between the magnets
Classify each phenomenon and write one sentence of evidence for your choice.
Pick one particle-motion case and draw its particles before and after a change, with arrows for motion.
Pick one field case and draw the two objects the field connects. Show what change would store more energy.
Trade drawings with another pair and check: does every field connect two objects, and does every particle drawing show motion?
Independent Practice10-15 minutes
Each student builds a four-frame model of a 0.20 kg pendulum released 0.45 m above its lowest point that swings until it stops. Frames: released at rest; passing the lowest point; at the far side; hanging still at the end.
In each frame students label where the energy is: in the Earth-pendulum gravitational field (0.882 J at release), in the motion of the whole bob, or in the random motion of particles of the air and the pivot. They compute the frictionless speed at the lowest point (about 2.97 m/s) and explain, with the particle model, why the final frame is slightly warmer but not visibly different.
Closure5 minutes
Exit ticket: "A ball is thrown straight up, stops for an instant at the top, falls back and comes to rest on the grass. Describe where the energy is at the top and after it stops, using only the words particle motion and field." Return to the warm-up drawings and ask students to fix the book drawing.
Differentiation Strategies
For Struggling Students
Give a two-column sorting mat labeled Motion of particles and Stored in a field, with picture cards for each phenomenon
Provide a drawing template: a box for the system, circles for particles, and a dashed line to show where a field connects two objects
Start with the rolling ball and the lifted book before introducing charged plates and springs
For Advanced Students
Ask students to explain why a moving ball's kinetic energy and the ball's thermal energy are both particle motion, yet only one of them can be fully turned back into lifting the ball
Have students use the simulation to find how the stored energy changes when the voltage, rather than the charge, is held fixed while the plates separate
Ask students to model chemical energy in a burning match as a change in the electric fields between atoms, labeled as going further than this lesson
Assessment Guidance
What to Look For
Check that every field model names the two objects the field connects, and that students no longer say the energy is "in the book". Look for particle drawings in which faster particles mean higher temperature and in which the ordered motion of a whole object is different from random motion. Listen for students who treat heat as a substance, and ask them what the particles are doing. For calculations, check units and whether the answer is physically possible.
02
Classroom Activities
3 Activities
1
Shake the Shot: Motion Becomes Thermal Energy
25 minGroups of 3-4
Groups put steel shot in a capped tube and turn it end over end many times, so the shot falls the length of the tube again and again. They measure the temperature rise, compare it with the maximum their model allows, and draw a particle model of what happened.
Procedure
Measure 0.50 kg of steel shot on a balance (use steel, never lead). Let the shot and tube reach room temperature and record the temperature of the shot.
Pour the shot into a 1.0 m cardboard mailing tube and cap both ends with tape over the caps.
Hold the tube vertical and flip it end over end 100 times, pausing so the shot falls the full 1.0 m each time.
Pour the shot into a foam cup and measure its temperature at once.
Safety: wear goggles, tape the caps firmly, and flip the tube away from other people.
Sample Data (invented)
Mass 0.50 kg, tube length 1.0 m, 100 flips. Temperature before 21.0 °C, after 22.6 °C. Largest possible energy from the field: 100 × (0.50)(9.8)(1.0) = 490 J, enough for a rise of about 2.2 °C. The measured 1.6 °C rise stands for 360 J, about 73% of the maximum.
Discussion Questions
The measured rise is smaller than the maximum the model allows. Where did the rest of the energy go? Use particle motion in your answer.
Draw the shot at three moments: at the top, falling, just after it lands. Which drawing shows ordered motion and which shows random motion?
Predict the rise for 200 flips, and say what assumption your prediction makes.
Modification for Distance Learning
Students analyze the sample data, then draw the three-moment particle model and record a 60-second video explaining it.
2
Simulation: Energy Stored Between Charged Plates
20 minPairs
Pairs use a free capacitor simulation (a computer model, one of the official model types) to see how the energy stored in the field between two charged plates depends on their separation. They compare the pattern with lifting an object in Earth's gravitational field, then feel a field for themselves with a balloon.
Procedure
In the simulation, set the plate area to 0.010 m² (100 cm²), charge the plates, and then disconnect the battery so the charge stays fixed.
Record the voltage and the stored energy at separations of 2, 4, 6 and 8 mm.
Sketch the field lines at 2 mm and at 8 mm.
Rub a balloon on your hair, stick it to a wall, then pull it away slowly and feel the pull. Describe where the energy goes as you pull. Safety: use balloons only (no high-voltage supplies), and check for latex allergies first.
Sample Data (invented, fixed charge 2.0 × 10⁻⁸ C)
Separation 2, 4, 6, 8 mm. Voltage 452, 904, 1,356, 1,808 V. Stored energy 4.52, 9.04, 13.56, 18.08 microjoules.
Discussion Questions
In these data the stored energy doubles when the separation doubles. How is this like lifting a book twice as high?
The voltage divided by the separation is the same in every trial. What does that tell you about the field between the plates?
Where does the extra stored energy come from when you pull the plates apart? What does your hand feel when you pull the balloon from the wall?
Challenge Variation
Keep the plates connected to the battery (fixed voltage) and repeat. Explain why the stored energy now decreases as the plates separate, and where that energy goes.
3
Energy Storyboards and Gallery Critique
25 minGroups of 3-4
Each group gets one scenario card and draws a four-frame storyboard (a drawing and description model) that tracks the energy from start to end, labeling every frame as particle motion or field. Groups then walk the gallery and critique each other's models with a checklist.
Scenario Cards
S1, skater: a 50 kg skater drops into a half-pipe 3.0 m deep and reaches 7.2 m/s at the bottom.
S2, baseball: a 0.145 kg baseball moving at 30 m/s is caught in a glove.
S3, soup: a microwave oven warms 0.30 kg of soup (c about 4000 J/(kg·°C)) from 20 °C to 60 °C.
S4, camera flash: a 330 microfarad capacitor charged to 300 V discharges through the flash tube.
Critique Checklist
Does every frame say whether the energy is particle motion or stored in a field?
Does every field connect two named objects?
Is there one calculation, with units, that fits the scenario? (S1: 1470 J from the field, 1296 J of motion; S2: about 65 J of motion; S3: 48,000 J of thermal energy; S4: about 15 J from the field.)
Does the model end with thermal energy somewhere, and is that plausible?
Discussion Questions
Only the skater card turns field energy into motion of a whole object. Which cards start with energy carried by fields, and which start with motion?
The skater's 7.2 m/s is less than the 7.67 m/s a frictionless model predicts. What does the missing 174 J look like in a particle model?
Which group's model would you most trust to predict a new situation, and why?
Modification for Distance Learning
Groups build storyboards on a shared slide deck and leave critique comments on two other groups' slides using the checklist.
03
Diagrams & Visual Aids
2 diagrams
Diagram 1: Particle Model of a Gas Before and After Heating
A particle model of the same gas at 300 K and at 600 K. Arrow length stands for speed and is drawn to scale: average particle kinetic energy is proportional to absolute temperature, so doubling the temperature makes each typical speed √2 ≈ 1.41 times larger. Thermal energy is this random motion of particles.
Diagram 2: Energy Stored in Electric and Gravitational Fields
Two field models side by side. Between charged plates the electric field is uniform, with evenly spaced field lines; near Earth the gravitational field is nearly uniform too. In both, changing the distance between the parts of the system changes the energy stored in the field.
04
Homework Assignment
~30 min
HS-PS3-2 Homework: Particle and Field Models of Energy
Directions: All data are invented for practice. Use g = 9.8 m/s², k = 1.38 × 10⁻²³ J/K, ε0 = 8.85 × 10⁻¹² F/m and cwater = 4180 J/(kg·°C). Every answer needs a drawing or a written model that says whether the energy is particle motion or stored in a field.
Part 1: Particle Models (Problems 1-2)
Air in a sealed syringe is warmed from 20 °C to 80 °C. (a) Draw a particle model of the air before and after, with arrows for motion. (b) Convert both temperatures to kelvins and find how many times larger the average kinetic energy of the particles becomes. (c) Explain why the plunger is pushed outward, using your model.
Water is stirred in an insulated cup by a hand mixer. The 0.50 kg of water warms as shown: t = 0, 2, 4, 6 min; T = 20.0, 20.9, 21.8, 22.7 °C. (a) Find the rate of temperature rise. (b) Find the power reaching the water. (c) Describe, with particles, how the motion of the beaters becomes thermal energy of the water.
Part 2: Field Models (Problems 3-4)
Two metal plates, each 0.20 m × 0.20 m, are 5.0 mm apart in air with 1500 V between them. (a) Find the field between the plates and check that it is below the 3 × 10⁶ V/m breakdown field of air. (b) Find the capacitance C = ε0A/d and the stored energy ½CV². (c) Draw a field model and mark where the energy is. (d) The plates are disconnected and pulled apart to 20 mm. By what factor does the stored energy change, and where does the extra energy come from?
A student writes: "A 2.0 kg book on a shelf 1.8 m above the floor has 35 J of energy stored inside the book." (a) Check the number. (b) Critique the model: where is the energy stored, and why does the answer depend on Earth? (c) Redraw the model correctly.
Part 3: Using Both Models (Problems 5-6)
1000 kg of water flows from a reservoir through a pipe to a turbine 50 m lower. (a) Find the energy released from the gravitational field. (b) If none were lost, how fast would the water move at the bottom? (c) Build a three-frame model: water in the reservoir, water rushing through the pipe, turbine and warmed water. Label each frame as particle motion or field.
Two small magnets, 0.010 kg each, are held apart and released. They pull together, click, and stop. A simulation says the magnetic field energy decreases by 0.030 J as they come together. (a) If the energy is shared equally as motion just before they touch, find each magnet's speed. (b) Model the energy before release, just before contact, and after the click, using only the words particle motion and field.
Rubric
Criterion
Full Credit (2 pts)
Partial Credit (1 pt)
Model
Drawing or description labels every energy as particle motion or field, and every field connects two named objects
Model present but one energy is unlabeled or a field has no second object
Calculation
Correct values with units and a check that the result is physically possible
Method correct with one unit or arithmetic error
Explanation
Uses the model to explain or predict, such as why the plunger moves or where the extra energy comes from
Explanation restates the calculation without using the model
05
Quiz: 20 Questions
Interactive, with answers
Instructions
All data are invented. Use g = 9.8 m/s² and cwater = 4180 J/(kg·°C). Your score updates as you answer, and Reset quiz clears everything so you or your students can try again.
Multiple choice: pick an option to check it. Short answer: write your answer, then reveal the model answer.
0 of 20 answered · 0 correct
Question 1 of 20 · Multiple Choice
A mug of tea cools on a table. Which model best accounts for its thermal energy?
Answer: C
Thermal energy is the random motion of particles; as the tea cools, its particles slow down on average. Choice A is the old caloric idea, which the particle model replaced. Choice B describes the energy of the tea's height. Choice D describes kinetic energy of the whole mug, which is zero when the mug sits still.
Question 2 of 20 · Multiple Choice
A flowerpot sits on a windowsill high above the street. Where is its gravitational potential energy stored?
Answer: A
The energy depends on the distance between the pot and Earth, so it belongs to the field that connects them. Choice B assigns it to one object alone. Choice C confuses stored energy with thermal energy. Choice D names the support, which only balances the force.
Question 3 of 20 · Multiple Choice
Which of these is energy stored in fields?
Answer: D
Drawing the bow stretches the string and limbs, pulling atoms slightly apart against the electric forces between them, so the energy is stored in electric fields between atoms. Choices A, B and C are all particle motion: the whole top turning, random motion in the hot bar, and organized vibration of air for sound.
Question 4 of 20 · Multiple Choice
A 6.0 kg bowling ball rolls at 3.0 m/s. What is its kinetic energy, the energy of all its particles moving together?
Answer: B
KE = ½mv² = ½(6.0)(3.0)² = 27 J. Choice A uses v instead of v². Choice C is mv, which is momentum, not energy. Choice D leaves out the ½.
Question 5 of 20 · Multiple Choice
A gas is heated from 250 K to 450 K. By what factor does the average kinetic energy of its particles change?
Answer: C
Average particle kinetic energy is proportional to absolute temperature, so the factor is 450 ÷ 250 = 1.8. Choice A squares the factor. Choice B is the square root of 1.8, which is the factor for the typical speed, not the energy. Choice D is the temperature difference, not a factor.
Question 6 of 20 · Multiple Choice
Two charged plates are disconnected from their battery, so their charge stays fixed. The gap between them is tripled. What happens to the energy stored in the field?
Answer: D
With fixed charge the field between the plates is the same, but it now fills three times the space, so the stored energy triples (U = Q²/(2C) and C falls to one third). The extra energy is the work done pulling the plates apart. Choice B reverses the relationship. Choice C squares the factor.
Question 7 of 20 · Multiple Choice
Two parallel plates 3.0 mm apart have 600 V between them. What is the electric field between them?
Answer: A
E = V/d = 600 V ÷ 0.0030 m = 200,000 V/m, safely below the breakdown field of air. Choice B multiplies instead of dividing. Choice C divides by 3.0 without converting millimeters to meters. Choice D converts 3.0 mm to 0.0003 m, a decimal error.
Question 8 of 20 · Multiple Choice
A student's model of a hot pan shows arrows of "heat fluid" pouring out of the metal into the air. What is the best improvement?
Answer: B
Thermal energy is particle motion, and it spreads when fast particles collide with slower ones, so the model should show that. Choice A keeps the fluid idea. Choice C misplaces thermal energy in a field. Choice D is false: collisions with air particles carry thermal energy away.
Question 9 of 20 · Multiple Choice
Water falls 25 m over a waterfall. If all the energy released from the gravitational field ends up as thermal energy of the water at the bottom, how much warmer is the water?
Answer: C
For each kilogram, gh = 9.8 × 25 = 245 J, and ΔT = 245 ÷ 4180 ≈ 0.059 °C. The mass cancels. Choices A and B are decimal errors. Choice D forgets to divide by the specific heat.
Question 10 of 20 · Multiple Choice
Sunlight warms a black car roof. Which model accounts for the energy best?
Answer: A
Light is energy carried by electric and magnetic fields through space, and when the roof absorbs it, its particles move faster at random. Choice B is wrong because space between the Sun and Earth is nearly empty of particles. Choice C confuses light with gravitational energy. Choice D describes kinetic energy of the whole roof, which does not change.
Question 11 of 20 · Multiple Choice
You pull two attracting magnets apart and hold them. What happens to the energy of the system?
Answer: B
Separating objects that attract stores energy in the field between them, just as lifting an object stores energy in the Earth-object field. The energy comes from the work your hands did. Choice A has the direction reversed. Choice D ignores stored energy, which does not require motion.
Question 12 of 20 · Multiple Choice
A 0.50 kg ball is lifted 2.0 m. How much energy is stored in the Earth-ball gravitational field?
Answer: B
ΔE = mgh = (0.50)(9.8)(2.0) = 9.8 J. Choice A leaves out g. Choice C uses only half the height. Choice D uses a 1.0 kg mass.
Question 13 of 20 · Multiple Choice
Which statement correctly compares the kinetic energy of a thrown ball with its thermal energy?
Answer: C
Both are particle motion: in kinetic energy the particles share one velocity, while thermal energy is their random motion around it. Choice A places kinetic energy in a field. Choice B places both in fields. Choice D is false: a ball at rest still has thermal energy.
Question 14 of 20 · Multiple Choice
Where is the chemical energy of a log of firewood stored, in the particle and field models?
Answer: D
Chemical energy depends on how charged particles (electrons and nuclei) are arranged, so it is energy stored in electric fields between atoms. Burning rearranges them and releases energy. Choice A is thermal energy, which a cold log has little of. Choice B is gravitational energy, which depends on height, not on the kind of wood.
Question 15 of 20 · Short Answer
A 100 microfarad capacitor is charged to 50 V. Find the stored energy and say where it is stored.
U = ½CV² = ½(100 × 10⁻⁶)(50)² = 0.125 J, stored in the electric field between the capacitor's plates.
Question 16 of 20 · Short Answer
A moving hammer hits a nail and stops. Describe what happens to the hammer's energy using a particle model.
Before impact, all the hammer's particles move together (kinetic energy). At impact the hammer and nail deform, and the ordered motion becomes random motion of the particles of the hammer, nail and wood, so they warm slightly. Some also becomes sound, the organized vibration of air particles.
Question 17 of 20 · Short Answer
A 0.50 kg hammer moving at 8.0 m/s strikes a 0.20 kg steel block 10 times and stops each time. If half the energy ends up in the block, find its temperature rise (csteel = 450 J/(kg·°C)).
Each blow carries ½(0.50)(8.0)² = 16 J, so 10 blows give 160 J and the block gets 80 J. ΔT = 80 ÷ (0.20 × 450) ≈ 0.89 °C, a small rise that the particle model explains as faster random motion.
Question 18 of 20 · Short Answer
A sled is pulled to the top of a snowy hill, released from rest, slides to the bottom and then coasts to a stop on flat snow. Account for the energy at the top, at the bottom of the slope and after the sled stops, using the words field and particle motion.
At the top the energy is stored in the Earth-sled gravitational field. At the bottom of the slope most of it is particle motion of the whole sled (kinetic energy), with some already random motion of particles from friction. After the sled stops it is random particle motion (thermal energy) of the runners, the snow and the air, which may melt a thin layer of snow.
Question 19 of 20 · Short Answer
Helium atoms in a balloon at 300 K have a typical speed of about 1370 m/s. Use the particle model to predict the typical speed if the balloon is cooled to 75 K.
Average kinetic energy is proportional to T, so speed is proportional to √T. The temperature falls to one fourth, so the speed halves: about 685 m/s.
Question 20 of 20 · Short Answer
A student's model says two parallel plates 1.0 mm apart in air can hold 5000 V to store energy in the field. Use the breakdown field of air (about 3 × 10⁶ V/m) to judge the model.
E = 5000 ÷ 0.0010 = 5 × 10⁶ V/m, which is above 3 × 10⁶ V/m, so the air would spark across the gap and the model fails. At 1.0 mm the voltage must stay below about 3000 V.
0 of 20 answered · 0 correct
06
Frequently Asked Questions
10 Questions
What does HS-PS3-2 mean?
HS-PS3-2 asks students to develop and use models showing that energy at the everyday scale can always be described in one of two ways: as motion of particles or as energy stored in fields. The code means High School, Physical Science, core idea 3 (Energy), performance expectation 2. The practice is modeling, so students draw, describe and simulate, not only calculate.
Does HS-PS3-2 have an assessment boundary?
No. HS-PS3-2 has no official Assessment Boundary. The Clarification Statement gives examples instead: kinetic energy becoming thermal energy, energy stored by an object's position above Earth, and energy stored between two charged plates, with models such as diagrams, drawings, descriptions and computer simulations.
What forms of energy count as motion of particles?
Kinetic energy of a whole object (all its particles moving together), thermal energy (random motion of particles) and sound (particles vibrating back and forth in an organized way). A useful test: if the energy is there because something is moving, it is particle motion.
What forms of energy count as energy stored in fields?
Gravitational, electric and magnetic potential energy, and also elastic and chemical energy, which are stored in electric fields between atoms. Light is energy carried by electric and magnetic fields. A useful test: if the energy depends on where things are relative to each other, it is stored in a field.
Why do we say gravitational energy is in the field and not in the object?
Because the amount depends on the distance between the object and Earth. Take Earth away and the lifted object has no gravitational energy at all. The energy belongs to the system of two objects, and the field is what connects them.
What kinds of models can students use for HS-PS3-2?
The Clarification Statement lists diagrams, drawings, descriptions and computer simulations. On this page students draw particle diagrams with speed arrows, draw field lines between plates, make storyboards and use a capacitor simulation. A good model makes a prediction that can be checked.
Is HS-PS3-2 taught in physics or chemistry?
It is usually taught in Physics or Physical Science, and it also fits Chemistry, where thermal energy as particle motion and bond energy as field energy are central. It pairs naturally with HS-PS1-4 on bond energy and with the energy unit of any physics course.
What misconceptions come up with particle and field models?
Common ones are treating heat as a fluid that flows, saying that energy is stored "in" a lifted object, and thinking that a field is empty space with nothing in it. Many students also think a still object has no energy at all, forgetting thermal and stored energy. Asking "what is moving?" or "which two things does the field connect?" addresses each one.
How is HS-PS3-2 different from HS-PS3-1?
HS-PS3-1 is about calculating energy changes in a system with a computational model. HS-PS3-2 is about explaining what energy is at a deeper level: every form is particle motion or field energy. The two work together: the numbers from HS-PS3-1 become more meaningful once students can say where each joule is.
What comes after HS-PS3-2?
HS-PS3-5 extends field models to the forces and energy changes between two objects interacting through electric or magnetic fields. HS-PS3-4 applies the particle model to thermal energy transfer between two components, and HS-PS1-4 uses field energy between atoms to explain energy in chemical reactions.
07
Related Standards
6 standards
These standards connect to HS-PS3-2: prerequisites to review first, parallel standards at the same level, and next steps that build on it.
Before this lesson
MS-PS1-4Prerequisite
Model how particle motion, temperature and state change as thermal energy changes
NGSS is a registered trademark of WestEd. Neither WestEd nor the lead states and partners that developed the Next Generation Science Standards were involved in the production of this product, and do not endorse it.
