Veritasium: Misconceptions About Heat

Contributor
Derek Muller
Type Category
Instructional Materials
Types
Animation/Movie , Phenomenon
Note
This resource, vetted by NSTA curators, is provided to teachers along with suggested modifications to make it more in line with the vision of the NGSS. While not considered to be “fully aligned,” the resources and expert recommendations provide teachers with concrete examples and expert guidance using the EQuIP rubric to adapted existing resources. Read more here.

Reviews

Description

This 5-minute YouTube video, hosted by physicist Derek Muller, aims to debunk specific misconceptions held by most people about heat and temperature. Dr. Muller uses an inquiry-based approach to explore the scientific meaning of heat transfer by examining whether our touch receptors are reliable gauges of heat and temperature. The opening question:  “Which is hotter, a metal hard drive or a paperback book?” (Both had been left outdoors for 4 hours).  Every participant answered incorrectly. All were sure the hard drive was a colder temperature because it “feels so much colder”.  An infrared thermometer showed that both objects were the same temperature. Next, Dr. Muller baked a cake. He asked participants to guess whether the cake tin or the cake itself would have a hotter temperature when he took it out of the oven. Again, all participants answered incorrectly, saying the cake tin would be much hotter.  And again, the infrared thermometer showed the temperatures to be almost identical. At the end of the video, Dr. Muller explains the science behind the phenomenon. The video addresses two widely-held misconceptions:  

1) Misconception 1: Human touch receptors are an accurate way to gauge temperature (they are not).

2) Misconception 2: Thermal energy is related only to temperature, but not to the material the object is made of. (Actually, an object’s material composition has a significant effect on its ability to transfer thermal energy. Metal objects are excellent conductors; paper and styrofoam are excellent insulators.)

 

Intended Audience

Learner
Educational Level
  • Middle School
Language
English
Access Restrictions

Free access - The right to view and/or download material without financial, registration, or excessive advertising barriers.

Performance Expectations

MS-PS3-4 Plan an investigation to determine the relationships among the energy transferred, the type of matter, the mass, and the change in the average kinetic energy of the particles as measured by the temperature of the sample.

Clarification Statement: Examples of experiments could include comparing final water temperatures after different masses of ice melted in the same volume of water with the same initial temperature, the temperature change of samples of different materials with the same mass as they cool or heat in the environment, or the same material with different masses when a specific amount of energy is added.

Assessment Boundary: Assessment does not include calculating the total amount of thermal energy transferred.

This resource was not designed to build towards this performance expectation, but can be used to build towards it using the suggestions provided below.

Comments about Including the Performance Expectation
As a short video, this resource is intended to spark student interest and introduce the discrepant event of temperature difference between a cold-feeling piece of metal and a warmer-feeling paperback book (both have been outdoors for the same amount of time; both are the same temperature).  The video will fit nicely into a unit exploring thermal energy transfer and definitions of energy. Temperature doesn’t measure “energy” per se. It measures the average kinetic energy  of the particles in a sample of matter. When two objects are left in the same environment for several hours, thermal energy will be transferred from the warmer-to-cooler object until both objects are at thermal equilibrium (same temperature). The rate of change in temperature is dependent on the type of matter and its mass. So why do human touch receptors sense a temperature difference between the piece of metal and the book when there is none? It’s about thermal conductivity (see DCI tips below.)

Science and Engineering Practices

This resource appears to be designed to build towards this science and engineering practice, though the resource developer has not explicitly stated so.

Comments about Including the Science and Engineering Practice
The video can be used as a springboard for students to brainstorm explanations. The host provides explicit stopping points through the video that invite prediction and brainstorming of explanations. Teachers may need to provide scaffolding to help students understand that transfer of thermal energy occurs any time objects of different temperatures interact.  Additionally, most students will need explicit guidance to understand that the scientific meaning of heat is quite different from our everyday definitions. In science, heat is defined as the thermal energy transferred due to the temperature difference between two objects.  Teachers: You may want to keep a Celsius-to-Fahrenheit converter handy at each learning station.

Disciplinary Core Ideas

This resource appears to be designed to build towards this disciplinary core idea, though the resource developer has not explicitly stated so.

Comments about Including the Disciplinary Core Idea
Understanding the scientific meaning of heat is a source of great difficulty in students of all ages, who often have firmly entrenched incorrect notions that make sense to them (i.e., “Temperature is the same as heat”, “We can gauge temperature fairly accurately by touching an object”, ‘Heat has nothing to do with the mass or structure of an object…..it’s all about temperature.”)  To dispel these incorrect ideas, try starting with Dr. Muller’s discrepant event:  have students touch a metal object and a paperback book and predict which is a higher temperature. Without giving the answer, introduce the “Misconceptions about Heat” video. Stop the video as Dr. Muller and his mother discover that the cake tin and the cake are both the same temperature. Ask students to explain what’s going on before playing the last 60 seconds of video.        Note to teachers: It may also be helpful to point out that the outdoor interviews were conducted on a chilly day (15 Celsius, which converts to 59 degrees Fahrenheit). For the cake experiment, the measured temperature of both the cake tin and cake was ~109 Celsius, which converts to ~228 Fahrenheit. A normal human body temperature averages about 98.6 degrees Fahrenheit. This means thermal energy will be transferred between the hand and the object because there is a temperature difference (see Core Idea above).  The human hands were a higher temperature than the book and hard drive; hands were at a lower temperature than the cake tin/cake. The reason the hard drive felt colder to the touch is because objects made of metal are better conductors -- the hard drive conducted heat away from the hand at a faster rate. Paper is a poor conductor, so the book felt warmer to the touch.  Similarly, the metal cake tin will conduct heat to the hand at a faster rate due to the molecular structure of metal. The cake itself will conduct heat more slowly, causing it to “seem” cooler to the touch.  So what are our hands actually detecting?  The rate of thermal conductivity.

Crosscutting Concepts

This resource was not designed to build towards this crosscutting concept, but can be used to build towards it using the suggestions provided below.

Comments about Including the Crosscutting Concept
This Crosscutting Concept can be the anchoring theme for introducing this particular video to tease out misconceptions about heat. In each of the scenarios in the video, thermal energy transfer is what drives the discussion. When objects are left outside for several hours, thermal energy is transferred between the object(s) and the ambient air in the environment. When human hands touch an object, thermal energy is transferred from one to another. (The energy is spontaneously transferred out of hotter regions into colder ones.) In science, heat is defined as the transfer of thermal energy from one object to another, due to temperature difference. The video will prompt students to question, “Why do some objects feel colder than others, even though they’re at the same temperature?” In exploring this counter-intuitive phenomenon, it will help to use thermal energy transfer as the anchoring concept to help students form correct ideas about thermal conductivity.

Resource Quality

  • Alignment to the Dimensions of the NGSS: The resource introduces a discrepant event to grab student attention and point out that temperature can’t reliably be gauged by touching an object. So when objects “feel” hot or cold to the touch, what are we actually feeling, if not temperature? We are sensing the ability of an object to transfer thermal energy through heat conduction. The video experiment leads students to a better understanding of the scientific definition of “heat”, which is the subject of Core Idea MS-PS3.A.4. Next, the video addresses the Middle School Practice within “Constructing Explanations” as the host provides explicit waypoints for pausing the video to make predictions and ponder possible explanations for why two objects seem (to our sense receptors) to be different temperatures, when they are the same temperature. This can serve as a precursor to understanding that thermal energy transfer between two objects depends partly on the type of material. Materials like metals will conduct heat more efficiently than others, which is why the metal cake tin feels hotter than the cake inside it. Last, the video explicitly addressed a Crosscutting Concept within  “Energy and Matter” as it depicts thermal energy transfer between objects of different temperatures (metal-to-hand and paper-to-hand).  

  • Instructional Supports: - none -

  • Monitoring Student Progress: - none -

  • Quality of Technological Interactivity: - none -