Exemplar videos

Examplar Videos

The examples of videos below were found to provide good illustrations of some or many of the framework components for the listed topic. However, developing a deep understanding of chemistry concepts requires multiple experiences with the material and these videos provide just one such experience. If you are seeking a deeper understanding of a specific topic, you might also want to see how the framework is defined for that topic. It can be helpful to understand how the core ideas and causal mechanistic reasoning could be articulated for the topic you are interested in.

For each video listed, we provide some strengths and weaknesses.

Acids

Exemplar Video 1	Exemplar Video 2	Exemplar Video 3
Comments This video provides a good overview of the inductive effect with respect to acid strength. It first explains induction and then talks about the importance of electronegativity and distance. It ends with a comparison of the relative strengths of Ethanoic acid and Benzoic acid using inductive effect to explain the differences.	Comments This video provided a strong overview on a lot of AB topics. He started with definitions for the first 3 minutes, then moved into talking about acids and their conjugates. Described how a conjugate base can be stabilized. He then explained pKa followed by pH/pOH.	Comments This video explains the effect of resonance on acid strength and compares ethanol with acetic acid. It evaluates the charge of both (-1) and atom carrying charge (both O). It then analyzes whether the atom holding the charge can form a resonance structure to delocalize the negative charge.
Strengths This video had strong multimedia principles and met the criteria for both CI and CMR. Our team rated this as "very helpful" because it was easy to determine what we should take away from the video.	Strengths This video contained a self-assessment portion for students from 8:00–8:30. The explanations were thorough and easy to follow; he also provided helpful equations to explain the concentration of acids and bases.	Strengths This video contains strong multimedia principles. It takes a very specific topic and dives thoroughly into why certain compounds are stronger or weaker acids.
Weaknesses This video did not contain macroscopic or particulate representations. It also contained misleading parts by personifying atoms.	Weaknesses This video did not contain macroscopic or particulate representations. It also contained misleading parts.	Weaknesses This video did not contain macroscopic or particulate representations of atoms.

Atomic Radii

Exemplar Video 1	Exemplar Video 2	Exemplar Video 3 by FreeSciencelessons Must be watched on YouTube. Time: 3:32
Description This video begins with a quick review of relative atomic sizes and their relationship to the periodic table, then provides a deeper explanation of why those trends occur. It compares nitrogen and oxygen, then lithium and sodium, using Bohr models and effective nuclear charge. It also compares sodium with sodium ions and oxygen with oxide ions using electron repulsion to explain differences in size.	Description This video discusses atomic and ionic radii. It explains why atoms do not have a clear boundary and defines atomic radius as half the distance between two bonded nuclei. It then describes trends down a group and across a period using particulate-level diagrams, shielding, nuclear charge, and electron attraction. The video also discusses ionic radii, including why cations are smaller and anions are larger than their neutral atoms.	Description This video describes trends in atomic radius across and down the periodic table. It reviews the periodic table, discusses how atomic radius is measured, uses a graph to identify trends, and explains period 2 using nuclear charge and electron shells. It also discusses shielding by inner electrons and uses Bohr diagrams for lithium, sodium, and potassium.
Strengths This video includes strong core ideas, science practices, and causal mechanistic reasoning because the instructor explains why the trends happen rather than only giving memorization rules.	Strengths This video makes strong use of Bohr models to show how and why atomic radius trends occur across and down the periodic table. It also provides causal mechanistic reasoning for both periodic trends and the size differences between cations and their neutral atoms.	Strengths This short video packs in a lot of quality content. It explains how atomic radius is determined and uses causal mechanistic reasoning to justify trends both across and down the periodic table. It also uses shielding to help explain the observed trends.
Weaknesses This video does not include a self-assessment for students to practice the concept they just learned. It also lacks an analogy and macroscopic representations.	Weaknesses The images are hand-drawn, so they are not as crisp as some other representations. The video is also lacking macroscopic representations.	Weaknesses The video scores low on multimedia criteria because the narrator is on screen the full time and the captions cannot be removed. It also misses an opportunity to make a stronger connection to macroscopic representations, since specific atom sizes appear in the graphs but are not explicitly connected in the narration.

Bonding

Exemplar Video 1	Exemplar Video 2	Exemplar Video 3
Comments Covalent bonding is the sharing of electrons resulting from attraction of nucleus of one atom for valence electrons of another. Covers attractive and repulsive forces involved and PE curve.	Comments This video focuses on how bonding impacts the physical properties of substances.	Comments Video focuses on ionic bonding
Strengths Up to 3:40 the video provides a focused and causal mechanistic level explanation of covalent bonding. The video clearly connects particle and symbolic representations and uses Science Practice of Developing and Using Models as it uses an animated potential energy diagram to show how the potential energy of the system changes as two hydrogen atoms approach or move away from each other. The decrease in energy when atoms come together is connected to energy release during bond formation and the requirement of energy to break bonds supporting a causal mechanistic explanation of covalent bonding.	Strengths This video focuses on the concept of how bonding affects physical properties of substances, comparing the properties of simple molecular substances to giant covalent structures (covalent network substances). It clearly connects the macroscopic physical property of boiling points and particle pictures for bromine (Br2) and diamond. Stressing that for Br2 weaker IMFs are overcome but for diamond to boil you must break much stronger covalent bonds. This clearly connects the structure to the property (Core Idea) and provides a scientific explanation (Science Practice) at the particle level which meets the expectations for CMR. It is very focused and provides multiple features to help learners organize content.	Strengths Makes good connections between symbolic/mathematical and particulate representations in explanation of why different compounds have different lattice energies. This is a causal mechanistic level explanation that addresses the core idea of Bonding and Interactions. The video contains a lot of the multimedia features that support learning. Good overview of content at the beginning, very focused and short video, has clear titles at the top of the screen to highlight what is being talked about, minimal text with good images to help support understanding. Closed captioning is accurate with punctuation.
Weaknesses After 3:40 the video moves into sigma bonds and pi bonds and then presents a table of bond energies. This material is not as focused and does not add meaningfully to the explanation from the first part of the video.	Weaknesses The content is stepped in; however, sometimes the screens get cluttered with a lot of information which might be distracting to some learners. The video is autocaptioned meaning there is no capitalization or punctuation.	Weaknesses The instructor is present on screen throughout the video which can be distracting to some. Though the video did explain differences in lattice energy, it could have connected this to the macroscopic property of melting points, which is more tangible to most learners.

Buffers

Exemplar Video 1	Exemplar Video 2
Strengths This video is high in pretty much everything. Video is split into two parts. The first part addresses how a buffer works starting with a macroscopic example and then goes through the development of a model using lego pieces to explain the macroscopic observations. The model development is particularly well done highlighting the observations that the model needs to explain and makes adjustments to the model when there are observations that it does not explain. Part 2 addresses the design of a buffer, starting with why you would want to make a buffer and highlighting the buffer system in blood. Again through model building and revision determines that a buffer must consist of a WA and its CB (or vice versa) AND addresses the idea of buffer capacity - you need enough of each component present to have an effect.	Strengths This video does a really nice job of grounding the concept of buffers in a phenomena (Clark Fork River). Uses a similare model and calculations to explain how a buffer works, and then ties back to the real world, more complext example.
Weaknesses The only weakness is its length. It is 17:28 which is longer than our typical videos, but is one of the best videos we have seen.	Weaknesses There are some side stories and many transitions between narrator, content slides, and demonstrations that could be distracting for novice learner. Also does not include particle representations to support student conceptual understanding at the particle level.

Enthalpy

Exemplar Video 1

Exemplar Video 2

Exemplar Video 3 - this video must be watched on YouTube

Comments

Short discussion of the energy differences between endo and exothermic reactions. Very clearly focused on the energy being tied to the bonds that are being broken and formed and how the balance between the two determines end vs. exo.

Drew reaction coordinate diagrams to explain.

Comments

Enthalpy of reaction - amount of energy being emitted or taken in during a chemical reaction as a result of bonds being broken and formed.

Gives example of nitroglycerin as an exothermic reaction (shows molecule), then talks about dynamite - stabilizes nitroglycerine by wrapping it.

Flow chart looks at amount of energy required to break bonds in reactants and the amount released when new bonds form in products and connects that to endo and exothermic reactions.

Talks about thermite reaction and shows energy diagram for the reaction (exothermic reaction). Shows enthalpy diagram.

If you turn the reaction around, enthalpy is the same amount but opposite sign.

Gives example of dissolution of ammonium nitrate. Moves to Born-Haber cycle and how it is a bunch of small reactions - example if making LiF out of Li and F2 gas - does not talk about what makes different parts endo or exothermic.

4:36-7:20 is Hess' law problem. Did you learn is the end part.

Comments

Explains enthalpy and that we measure change in enthalpy, not enthalpy.

Shows a neutralization reaction on a reaction coordinate diagram and an endo reaction.

Strengths

This lesser viewed video pulls together a strong conceptual description of endothermic and exothermic reactions.

The video clearly articulates the energy changes associated with both bond making and breaking. In doing so, it makes strong connections between the symbolic and particulate representations.

Throughout the video, the narrator uses the core idea of energy with enough depth that met the Causal Mechanistic Reasoning expectations when answering the question “What results in an exo or endothermic reaction?”

The video itself was strong in all aspects of Mayer’s multimedia principles that were assessed.

Strengths

This video provides a very good summary of how the balance of energy required to break and form bonds results in the net change in energy.

The video provides macroscopic examples and links those to the symbolic graphical representations of an energy diagram.

In providing the description, the video employs the Energy core idea and does so in enough depth to achieve a Causal Mechanistic Reasoning answer.

The video also provides a reminder of the key expected learning outcomes at the end.

Strengths

This video begins with very clearly articulated learning objectives.

The video addresses the concept of enthalpy by defining it and provides a representation of the macroscopic impacts that enthalpy can have (changing temperature as a result of a chemical reaction).

Lastly, the video takes an in-depth look at the reaction energy diagram and shows the difference in representation between an exothermic and endothermic reaction, including activation energy.

The video effectively addresses the idea of Energy as a core idea as well as using the Science Practice of constructing explanations to explain why neutralization reactions are exothermic.

Weaknesses

Because the video did not bring in a real world phenomena, it did not meet the criteria for Science Practices.

Right at the beginning of the video, there was one potentially misleading part where it was stated that molecules could not react if we did not add heat.

Although activation energy is indeed required for reactions, it is often the case where ambient temperature provides enough energy for the reaction to proceed without additional heat.

Weaknesses

Throughout the video, the narrator can be seen on screen which can be distracting for some viewers.

The video also contains a significant section on Hess’s Law.

This is used through the process of rearranging and adding equations to determine the change in enthalpy for a reaction.

Although nothing is incorrect, this aspect was outside of the broader conceptual focus defined for this topic.

Weaknesses

The video itself has the speaker shown constantly and has captions directly on the video (cannot be turned off).

Each of these can be distracting for some students.

The video also lacks the level of depth to achieve causal mechanistic reasoning.

In many ways, the video seems to focus more on being able to draw out the reaction coordinate diagram rather than fully understanding the concepts behind it.

Entropy

Exemplar Video 1

Exemplar Video 2

Exemplar Video 3

Comments

Starts with messy room analogy and says while it is easy to see and understand, it is misleading. Prior knowledge: energy is quantized and definition of system and surroundings. Learning Objectives: Describe the concept of a microstate and discuss what entropy measures conceptually.

Examples of spontaneous processes - definition. Gives pictures of spontaneous processes. Specific example - inflated balloon that has not been tied and is then let go. Gas that was in the balloon is now dispersed. Then food dye dispersing in water. Then hot pan cooling. 2nd law.

Defines it in words and symbols. Measure of the number of ways energy can be distributed in a system of molecules. Uses dice analogy to talk about microstates (ways you can get to) for each macrostate (sum of 2 dice). Heat transfer example - one heated to 60°C and the other at room temperature. When you push them together, they equilibrate. Shows thermal imaging and connects this to the 2nd law equation.

Comments

Started with looking at dye dissolving in water through an analogy, then moved to actual dye. Followed up with a good example of how dye molecules will be more likely to disperse based on probability, including with Boltzmann calculations.

Hit on how temperature impacts entropy. Discussed how systems might get more ordered (e.g., water freezing, iron rusting). Lastly discussed concept of Gibbs Free Energy and the equation.

Comments

Entropy is related to microstates. Considers n moles of gas at a given P, V, and T. Macroscopically, nothing is changing. Particulate level: particles can be in different positions and velocities at any given time. Shows 3 possible states of 4 particles (3 microstates).

Microstate = microscopic arrangement of all positions and energies of gas particles. Shows the equation that relates entropy to the number of microstates. If W (microstates) increases, S increases. Described as increase in disorder or dispersal of matter or energy.

Uses diagrams to explain entropy change in various cases: increasing volume, increasing temperature, gas reactions with changing moles. Excellent explanation of particle speed distribution and entropy. Summarizes: more microstates → positive entropy change.

Strengths

This video addresses every aspect of Johnstone’s Triangle and makes clear connections between levels. Uses dice probability analogy to explain macro/microstates and incorporates opportunities for self-assessment.

Applies science practices (Developing Models, Using Math/Computational Thinking) to explain energy. Strong causal explanation of temperature equilibration with models, numbers, and microstates.

Covers entropy topics including 2nd law, microstates, entropy calculations. High multimedia quality: low extraneous load, well-structured, and focused on key concepts for learning.

Strengths

Begins with M&M analogy for mixing, extends to dye in water. Provides particulate models and explains behavior based on microstates and probability, meeting science practice expectations.

Explores water freezing with a quantitative entropy calculation and real-world interpretation. Covers core ideas: Change & Stability, Energy, Particulate Nature of Matter. Includes a question prompt for engagement.

Strengths

Effectively connects symbolic and particulate levels using simple diagrams. Gives specific examples with clear representation of entropy changes (e.g., increasing volume, temperature, number of moles, or evaporation).

Meets science practice expectations using models and causal reasoning. Emphasizes that increasing disorder = increasing microstates. Clean, focused delivery without distracting effects.

Weaknesses

Examples of spontaneous processes are given early but not connected to entropy until around the 6-minute mark. Captions are missing for about 2 minutes, disadvantaging some learners.

At 13 minutes, it’s a bit long, which may lead to students skipping parts.

Weaknesses

Lower scores on multimedia evaluation for text and coherence. Text stays on screen too long and the constantly shifting background may distract learners.

Weaknesses

Whiteboard-style video sometimes gets visually cluttered due to underlining and circling. Lacks structural organization (e.g., intro, section breaks, summary).

Refers to particles as “microscopic” when technically they are sub-microscopic. Minor, but worth refining for scientific accuracy.

Gas Laws

Exemplar Video 1	Exemplar Video 2	Exemplar Video 3
Comments Gives graphical depiction of relationship between P and V. States Boyles Law. Shows container with piston and pressure guage and particles in it. Shows how when you decrease the V the particles hit the walls of the container more frequently and P goes up. Moves to mathmatical relationship PV = k and then a couple of example problems using P1V1 = P2V2. Then ends with other gas laws.	Comments Defined gas properties, discussed how changing one property affected another using particle motion (visually and verbally), connects to individual gas laws, presents combined gas law and ideal gas law, gives some practice using ideal gas law to do calculations.	Comments The video briefly explains the differences between real gases and ideal gases and how to apply to kinetic molecular theory to ideal gases.
Strengths This video effectively uses and connects the different levels of representation to help the viewer understand Boyle's Law. In the initial overview of the concept, the narrator makes connections to the core idea of Change and Stability in how she connects the impact of volume changes on the resultant pressure using the science practice of developing and using models.	Strengths This video addresses multiple core ideas (Change and Stability and the Particulate Nature of Matter) while also engaging in a Science Practice of Using Mathematical and Computational Thinking. Further, the presenter provides causal mechanistic reasoning when explaning how different gas properties interrelate.	Strengths This video uses strong particle representations to help make connections to the macroscopic and particulate level representations. Further, the narrator makes clear connections to the core ieas of Change and Stability and the Particulate Nature of matter. The video also provide Causal Mechanistic Reseoning related to why real gases deviate from ideal behavior. This video exhibits strong organizational characteristics with an overview on the front end and a summary at the back end.
Weaknesses The organizational flow could have been improved to better help the viewer understand the key points and provided a clearer summary at the end.	Weaknesses The organizational flow could have been improved to better help the viewer understand the key points and provided a clearer summary at the end.	Weaknesses The video has the speaker on screen throughout the video, which can be distracting. Also, at 7:49 an equation that is not always true is put on the screen.

Intermolecular Forces

Exemplar Video 1	Exemplar Video 2
Strengths Provides very good segmenting through flow chart at beginning and end. Provides an animation and explanation of how induced dipole forms and gives many examples of how different atoms have more/less LDF which leads to macroscopic properties like protein folding and boiling point.	Strengths Good overview on all the types of interactions and shows the particles oriented correctly. Connects concept of electronegativity and dipoles and the relative strength of charge to strength of IMF attraction. Clearly articulates hydrogen bonding is dipole and all atoms have LDF. Shows example vector analysis.
Weakness Instructor on screen, only covers LDF.	Weakness Instructor on screen, says energy is stored in bonds and does not clearly state energy is used to overcome IMF/electrostatic attraction, but to overcome energy stored in bonds. Honestly, 0:00-5:20 is really good. Second half is good but kinda drags on.

Ionization Energy

Exemplar Video 1	Exemplar Video 2	Exemplar Video 3
Description This video compares first and second ionization energy using lithium as an example. It provides a Bohr diagram of lithium, gives the value for the first ionization energy, and then shows the second ionization energy after the first electron has been removed. The video explains the large difference between the two values using nuclear charge, effective nuclear charge, shielding, and distance from the nucleus.	Description This video begins with an overview and definition of ionization energy, then introduces second ionization energy. It discusses factors that influence ionization energy, including radius, nuclear charge, shielding, and distance. The video compares lithium and potassium using specific values, summarizes the trend down a group, examines the trend across a period, and then addresses successive ionization energies using data for the first through eleventh ionization energies.	Description This video begins with the second row of the periodic table and the ionization energy values for those elements. It identifies the general trend and then uses effective nuclear charge to compare lithium and beryllium. The video also explains deviations in the trend, including the difference between beryllium and boron using 2s and 2p orbital distance and repulsion, and the difference between nitrogen and oxygen using pairing energy.
Strengths This video addresses effective nuclear charge and multiple ionization energies while providing specific ionization energy data.	Strengths This video provides specific numeric ionization energy data, addresses multiple ionization energies, and explains effective nuclear charge.	Strengths This video addresses effective nuclear charge and provides exact ionization energy data.
Weaknesses The screen becomes a little messy by the end because of the circling and added information placed on top of the graphics.	Weaknesses This video ranks low for text because it consists mainly of an instructor talking over prepared notes and highlighting them.	Weaknesses This video ranks low in segmenting because there are no noticeable organizational tools for students.

Kinetics

Exemplar Video 1	Exemplar Video 2	Exemplar Video 3
Strengths The strengths of this video are that it uses a PhET simulation to show how energy and orientation are important for successful collisions and how increasing the temperature can speed up particles and result in more successful collisions.	Strengths This video uses the framework of collision theory: to react, particles must collide, must collide with the correct orientation, and must collide with enough energy to overcome the activation energy barrier. For each factor, the video examines how changing it impacts each of these aspects of collisions to explain how reaction rate is affected. It also uses particle representations when explaining all factors.	Strengths The video indicates that it will discuss factors affecting rates of reaction and then lists those factors to provide an organizing framework for the learner. Explanations for each factor are clearly delineated, and a summary is provided at the end. The video provides particle-level representations to support explanations, and the explanations are grounded in collision theory.
Weaknesses The weakness of this video is that it only talks about how some factors, such as concentration, pressure, and surface area, can affect the rate of a reaction and does not actually show these in terms of particle interactions. It also tries to include several things in a relatively short video, which means the depth of explanation is not as strong as in some other videos.	Weaknesses The particle representations are static. Given the dependence of reaction rate on collisions, using an animation to show moving particles and collisions could improve these explanations.	Weaknesses Some segments of the video mix macroscopic and particulate-level representations, which could be misleading for students. For gases, instead of using round particles to represent atoms or molecules, the video uses clouds to represent gas particles. This could prompt students to think that gases are not matter made up of atoms or particles like solids or liquids.

LeChatelier's Principle

Exemplar Video 1	Exemplar Video 2
Strengths The strengths of this video lie within its representations of the topic. This is one of the few videos that represent the topic of Le Chatelier’s Principle at each the macroscopic, symbolic, and particulate levels. The video also makes solid connections across the levels. The video also engages in the science practice of Developing and Using Modles. The video also exhibits very strong organization as it provides an overview at the beginning, chapters through the video, and a summary at the end.	Strengths The strengths of this video lie within the content. This video was one of relatively few that really focused on the rates of the forward and reverse reactions and how it is changes in these that lead to changes in the equilibrium. This allowed the video to score high on both the core ideas and it provided causal mechanistic reasoning. Because there were no actual phenomena presented, the explanations did not meet the criteria for the Explanation Science Practice.
Weaknesses The weaknesses of this video lie within the content. Although the video discusses the content at a level suitable to answer questions in many general chemistry classes, the explanations provided did not actually link to the core ideas nor did they provide a level of depth for Causal Mechanistic reasoning. Although most aspects of our multimedia scored high for this video, having the instructor on screen for the full time scored low in the coherence category. Lastly, it is worth noting that the video employed the balance as an analogy, which we define to be misleading, as students often connect the idea of equality to the reactants and products rather than the rates of the forward and reverse reactions.	Weaknesses The weaknesses of this video revolved around the overall approach. The video only presented the topic at the symbolic level. Further, the approach of having a person on the screen in front of a white board meant that it scored lower on several of the multimedia criteria. Further, the video was only autocaptioned, so there was no punctuation or capitalization.