How Does Heat Move? Introduction to Heat Transfer

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Objective

The student will be able to identify and explain the various ways that heat transfers through systems in the natural world.

Big Idea

Students analyze a text to find evidence of heat transfer and connect the evidence they cite from the text to fun demonstrations!

Introduction and Connection to the NGSS and Common Core

This lesson represents the students introduction to heat transfer.  Students are introduced to conduction, convection and radiation through a text analysis and a series of demonstrations and then they participate in labs in which they identify evidence of each.  While it is listed as one lesson here, this lesson spans two class periods.

This lesson is geared to address the following NGSS and Common Core Standards:

MS-PS3-3   Apply scientific principles to design, construct, and test a device that either minimizes or maximizes thermal energy transfer.

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.

MS-PS3-5  Construct, use, and present arguments to support the claim that when the kinetic energy of an object changes, energy is transferred to or from the object. 

CCSS.ELA-LITERACY.RST.6-8.3  Cite specific textual evidence to support analysis of science and technical texts.

CCSS.ELA-LITERACY.RST.6-8.9  Compare and contrast the information gained from experiments, simulations, video, or multimedia sources with that gained from reading a text on the same topic.

In this lesson, students construct, use and share oral and written explanations (SP6) to support a claim explaining an unexplained phenomena that is supported by textual evidence (SP7).  In doing this, students gain an understanding that the transfer of energy can be tracked as energy flows through a designed or natural system (Cross Cutting Concept Energy and Matter).

Warm Up: Formative Assessment on Kinetic Energy Relationships

10 minutes

In the previous lesson, students went through a series of lab stations focusing on these learning targets:

  1. I can construct and analyze graphs, charts, and figures that show the relationship between kinetic energy and the mass and speed of an object.
  2. I can provide evidence that the amount of energy needed to transfer to change the temperature (average kinetic energy of the particles) of an object depends on the type of matter and the mass of the object.
  3. I can support the claim that when the kinetic energy of an object changes, that energy has been transferred to or from the objects in the system (energy is conserved).

As a formative assessment of their level of understanding in these topics, students complete this warm up.  Students at this point have been working on developing diagrams.  To see the introductory lesson to diagram drawing, check out this lesson.  To look at the lesson that led up to this formative assessment, check out this lesson.

For the first diagram, this student identified that a copper pot and a nickel pot would heat up differently.  The student includes a title, labels, and a caption.  One important thing that this student did is use a real world situation as opposed to a lab situation.  Many students can draw a diagram here that shows a lab we have already done in class.  While some understanding can be shown by doing this, real independence can only be shown when students can apply it to a new or different situation.  

One common mistake students make in this diagram is that they do not connect that the kinetic energy they are supposed to be referencing is thermal energy or temperature.  Even though it says it explicitly in the question, students may not realize temperature is a measure of kinetic energy. Many students will draw examples of different objects showing different amounts of mechanical energy because when they think of kinetic energy they think of an object physically moving.

For the second diagram, the student again includes a title, labels, and caption that show how the amount of kinetic energy transferred depends on the mass of an object.  The student shows a ball of wood and a ball of metal being thrown in the sand.  The student explains in the caption that the metal ball will create a bigger crater because it has a larger mass.

During the following lesson, I conference with small groups of students based on similar needs.  I sort these slips into stacks of learners.  For example, I may have a group of students that drew diagrams of lab situations instead of real world situations, a group of students that do not adequately explain their picture in their caption, and a group that did not make the connection in the first diagram that the kinetic energy they were supposed to describe was thermal energy (temperature).

Connecting to the Essential Question: What are you going to learn today?

5 minutes

Ask students, "What are you going to be learning today?".  Students should respond with the essential question, "How does energy transfer through various systems in the natural world?" (I keep this posted on the board.  Students also have it in their Unit Plan).

Explain that the students will specifically be introduced to Skills 3, 4, and 5 listed in the Unit Plan:

  1. I can solve problems based on my understanding of heat transfer (conduction, convection, radiation).
  2. I can provide evidence that the amount of energy needed to transfer to change the temperature (average kinetic energy of the particles) of an object depends on the type of matter and the mass of the object.
  3. I can support the claim that when the kinetic energy of an object changes, that energy has been transferred to or from the objects in the system (energy is conserved).

Ask the students to take some time to read each skill.  As they read, have them underline the key vocabulary in the skill and circle the key verbs (the words that explain what the students have to be able to do with their learning.).  Then, ask the students to rank themselves on a scale of 1 to 4 (4 being mastery) on each skill and write this number next to the skill on their Unit Plan.

**Important Note:  As this is their introduction to heat transfer, it is critical that students assess their level of understanding on this day.  Without this original self-assessment, it is challenging to chart and monitor growth in each skill.

Then, ask the students to make as many connections during the lab to the following ideas/concepts:

  1. Conduction, convection, and radiation
  2. How the type of matter or mass of an object affects heat transfer
  3. How energy can be tracked through a system (that when one object gains energy, another loses energy)

Remind them if at any point during the lab they connect to any of these ideas, they should share that connection with you or a fellow student!

Engage: What is temperature? Demonstration

10 minutes

Explain to the students that as discussed, one of their focuses today is going to be heat transfer.  They are going to be focusing on how heat transfers in various systems in the natural world.  I usually set the students up for the upcoming demonstration by saying, "What do you think of when you think about heat?".  Students may offer a wide range of suggestions; however, keep them going until you hear a student offer "temperature".  Ask students "What does temperature mean?" Typically, students say, "How hot or cold something is".  This is a big misconception that is challenging to break.  I then say, "Interesting definition.  I want to take you through a demonstration and see if you might change your definition after watching it."

Demonstration:  What is temperature?

In this demonstration, fill a beaker with warm water and a beaker with cold water.  In addition, have a beaker set between them with room temperature water.  Ask for two volunteers, but emphasize to them that they are at no point allowed to speak.  Ask one student to place their hand in the hot beaker (don't call it the hot beaker - just point) and the other student to place their hand in the cold beaker (don't call it the cold beaker).  Have them keep their hands in the beakers for a few seconds, emphasizing that they are not allowed to speak or make visual demonstrations of what they are feeling.  Then, ask one of the students to place their hand in the middle beaker and quietly without anyone seeing write on a sticky note if the water in the middle was hot or cold.  Repeat this process with the other student.  Have each student share with the class their sticky notes.  The student whose hand was in the hot water will write, "Cold" and the student whose hand was in the cold water will write, "Warm".  

Ask the students, "How is that possible?  If the definition of temperature is 'how hot or cold something is', how could they each say the temperatures were different?".  Provide wait time and let students think.  Then, ask the student volunteers to explain what they experienced from the start to the finish of the demonstration.  Then, allow students in the class to share their ideas of what occurred.  Hopefully, students offer suggestions about heat transferring from a higher temperature to a lower temperature.  Explain that temperature is the measure of the kinetic energy of the particles in matter, it is not how hot or cold something is.  "Hot" and "cold" are just terms we use that indicates the way the energy is transferring.  

Mini Lesson: Heat Transfer and Obtaining Information From Text

45 minutes

Provide students with the Heat Transfer Reading from Rader's Science4Kids.

Remind students that effective readers are doing far more than just reading the words as they interact with a science text.  Effective readers are constantly evaluating vocabulary, formulating questions, making text to self connections, and connecting to scientific content as they read.  Making these connections visible can greatly improve reading comprehension.  In my school district, we call this "talking to the text".  

Model for students how to interact with text as you read the first paragraph of the article.  Then, provide students with time to talk to the text for the entire article.  Remind them to make connections to the essential question and to the skills we are working on today.  The video below shows me modeling "talking to the text".  In addition, I have included a resource that shows what a completed article might look like following "talking to the text".

 

After students finish reading the article engage in a conversation with them about what they read.  Ask students to share some connections or things they wrote when they "talked to the text".  It is important that students share this for the class.  It will benefit readers that are not making connections to see the connections other students are making with the text.  Furthermore, as students share, ask them to state the heading title and line in which they are making the connection.  This way, other students in the room can see if they made similar or different connections than the speaker. 

Remind students that our purpose today was to make connections to Skill 3, 4, and 5 and the essential question.  Ask them to specifically share what they found in connection with these skills:

  1. I can solve problems based on my understanding of heat transfer (conduction, convection, radiation).
  2. I can provide evidence that the amount of energy needed to transfer to change the temperature (average kinetic energy of the particles) of an object depends on the type of matter and the mass of the object.
  3. I can support the claim that when the kinetic energy of an object changes, that energy has been transferred to or from the objects in the system (energy is conserved).

Next, explain that you are going to take the students through a series of demonstrations.  Then, you are going to ask them to cite evidence in the text that can help them explain what type of heat transfer is occurring.  It is important that scientists connect and cite textual evidence in their explanations.  Instead of just saying, "I think" explain that they are going to refer to the place in the text that provided you with evidence of the conclusions they make.  As they watch each demonstration, students should be doing more than just "enjoying the show".  They need to always be thinking, "How does the text help me explain the heat transfer that is occurring?".

 Demonstration 1:  Lightbulb in a Microwave

In this demonstration, place a lightbulb in a beaker of water and place it in the microwave for about 15 seconds.  Place the microwave so that students can see what's happening inside.  The lightbulb lights up!  The students in my class have seen this demonstration before, but in a different lesson with a different focus.  I like reusing demonstrations (especially cool ones!) and shifting the purpose so that students can see that in every phenomena there are multiple scientific principles that can be seen.  

After watching the demonstration, students share with the class what type of heat transfer they witnessed.  Emphasize that they must explain it through the scope of the text.  They must use the text as evidence to strengthen their claim.  This is a challenging skill!  Students are going to want to just say things such as, "It's radiation, because of the microwaves."  However, this claim is not strengthened by a text reference.  Instead, a student might say, "This was radiation.  In the text "Energy Likes to Move", in the section "Radiating Energy", it stats that radiation is carried by electromagnetic waves.  In this demonstration, there were microwaves and light from the lightbulb that are forms of EM waves."

Demonstration 2:  Thermal Dynamics Mechanism

I purchased my Thermal Dynamics Mechanism.  There is a cup of hot water and a cup of cold water.  A metal rod with a motor and spinner is placed so that one end of the rod is in the hot water and one end of the rod is in the cold water.  The heat transfer powers the spinner.

Again, have students cite evidence from the text to prove what type of energy transfer was occurring.  Make sure they are citing directly from the text to back up their claim that conduction was occurring as the energy transferred from the hot to the cold water.  Students might say something like, "In "Energy Likes to Move", the section "Conducting Energy and Heat" states that when the heat source and heat sink are connected the energy transfers through collisions towards the heat sink.  In this case, the molecules in the hot water collide with the metal rod and the energy is transferred towards the cold water."  Some students may even reference the "temperature gradient" and how the large difference in temperature in this demonstration caused a large amount of energy to be conducted.

Demonstration 3: Convection in Boiling Water

On a hot plate, boil a pot of water.  Once the pot is at a full boil, drop a piece of colored thread into the pot and have the students watch its movement.  The thread will move towards the edge of the pot, sink, and then rise again in a cycle.

Have students cite evidence from the text to prove what type of energy transfer was occurring in the pot. The great thing about this demonstration is that while most students will cite convection as the heat transfer, students could also cite radiation and conduction as well.  If students do not offer these options, prompt them to think about other types of energy transfer that could be occurring so that they do cite evidence of both.

This is a great opportunity to connect back to the essential question that references that energy transfers through systems in the natural world.  Explain that radiation, conduction and convection work together to heat the atmosphere as well.  Radiation from the sun heats the ground when it is absorbed; the warm ground conducts heat to the air above it, warming the air; and that warm air rises and then cools as it gets farther from the earth and sinks back down again in a convection cycle.

Shape Vocabulary: Conduction, Convection, and Radiation

20 minutes

This activity could take much longer or shorter depending on how you use it.  If you have each individual student complete this and present their final products, it could take 45 minutes.  If you have students create the shape vocabulary but not present all of them, it might take 20 minutes.  At the other extreme, you could assign this as homework and not use classroom time at all!

I provide each table with a white board and a dry erase marker.  If you do not have small white boards white paper and markers would work as well. I ask each person to write the words conduction, convection and radiation in the shape of its definition.  I tell the students that they can add small pictures, but the way that the word is written should be in a shape that shows meaning.  For example, students during our waves unit wrote the word "absorption" before and after a sun shining on sun glasses.  They explain that they wrote the "ABS" larger on the sun side of the glasses and the "orption" smaller on the other side because some of the rays were absorbed by the glasses.

Below are some examples my students created:

 

This student showed radiation by writing the word "radiation" as a ray from the sun.  The student explained that the sun produces electromagnetic waves as radiation.

This student wrote convection in a cyclical pattern to show the rising of warmer, less dense water and the cooler, more dense water that sinks to replace it. 

This student explained that they wrote "cond" as molecules in the foot and "uction" as molecules in the hot sand.  The student explained that these molecules bumped into each other, transferring energy.

Closure

5 minutes

Have the students at each table share their shape vocabulary and choose one to share with the class.  Each group should present to the class their table's chosen shape vocabulary and explain how the picture shows the meaning.