Lesson 11 of 11
Objective: SWBAT describe how the parts of a system are effected by heat transfer.
This lesson requires very little in the way of materials
For this lesson you will need one "bird" for each group of students. If resources are limited, you could get away with watching a video of the bird in action or have one on hand to demonstrate, but these toys are really fun to interact and experiment with and are very inexpensive so it worth the investment to have some on hand. I have 10 on hand in case any break but also to have some demonstration birds to show what they look like when their are in equilibrium (more on this later).
Here is a link to a website that sells a pack of three for about $16.00.
I addition to the birds, you will need a tray and a beaker of water. That's it!
Have some poster paper and sticky notes on hand for students to post their questions.
As students walk into the class I have a drinking bird set up in the front of the class. Just before they enter, I wet the beak and start it moving.
Five trays are prepared and sitting along the counter, each with a bird and a full beaker of water. These birds are also already cycling.
I begin by asking students if they have ever seen one of these birds. A few hands go up.
I then ask them what they know about the birds. I call on a few students and listen to what they have to share.
Ask them what they are wondering about and record a few responses but do not give away too much at this point.
I'm using an inquiry strategy of having students think of a question, and then they'll use their questions to shape an investigation. This approach is not only more engaging because it is student generated (and thereby owned by the students), it also generates deeper thinking because the ideas, the investigation, the questions, and the probable outcomes are not given to them - these must all be "found".
Next, I tell students to observe a bird and as they work with their group to identify the following:
- How is the bird a system? What are the parts of the system?
- The bird cycles through different positions. What are the steps of the cycle? Pick a starting point and list the steps you see.
- Where does heat transfer occur in the system? (SP6 Constructing Explanations and Designing Solutions - Construct an explanation that includes qualitative or quantitative relationships between variables that predict(s) and/or describe(s) phenomena.)
Give them plenty of time to discuss with their table group. Encourage them to draw their ideas in their journal and record their observations in words and pictures with annotations.
A note here about vocabulary. Cycles and Systems in Nature are a reoccurring theme in all of my lessons. I teach integrated Earth Systems science so use as many opportunities as I can to get my students thinking about the interrelated nature of the world. It is our job as science teachers to cultivate systems thinkers. Developing critical thinking skills is part of being a systems thinker.
If your students are not familiar with these concepts, take the time now to define a system and a cycle and return to these definitions frequently.
This model has some complex steps some which are explicitly visible and others that are not. Much like the complex interactions in Earth systems, a deeper look at cause and effect relationships coupled with a discourse from evidence and reasoning that includes accessing prior knowledge (heat transfer, kinetic molecular theory, etc) is a comment of student processing. Ask your students to think about inputs and outputs of energy transfers in this model and what the parts of the system are. This is example of applying the cross cutting concept of Systems and System Models.
Keep track of the time as you want about 15 minutes to bring the class back together and have them share their ideas.
I like to have students record what they are wondering on sticky notes and post them on poster paper. We will keep these up and return to them as we progress through this or a series of lesson.
Have a sheet of poster paper with a title, something like "What we are wondering about...."
Give each table a enough sticky notes for 1-2 per person and have every student record an observation and a question.
I frame it with language stems,
- I am wondering....
- I observed....
- This makes me think.....
- I want to know more about....
Give students time to write then have them come up and post their notes on the poster. In the video below, you'll hear my students state their thinking as they come up to post it on our "Wondering" chart. Both of these students are thinking about temperature, perhaps because it presents an obvious contrast. Note that the first student articulates her thinking about temperature more precisely, but lacks confidence in her thinking.
This slide show displays some of the student responses. Notice the evidence for the building of systems thinking from their ideas on steps in the cycle, heat transfer, and how the bird is analogous to other systems. They are seeing and wondering about the parts of the bird and the interactions from one part to another.
A note here about timing.
I introduce this lesson as we begin our study of heat transfer and then revisit it again at the end so the there is a 2-3 week gap between the first part of this lesson above and what follows from this point.
For this part of the activity, students start revisiting their ideas on what is cycle and a system and look back at their journal notes from the first time we explored the birds.
Building on what they have learned about heat transfer, density, fluids, etc, ask them to identify what keeps the bird moving and why; what would cause it to stop and why. You want them to revise their thinking and dig deep for understanding.
Give them some vocabulary to use in their explanations:
- phase change
Tell them to think about why you have included these words and where we have studied them in previous labs and investigations. I embrace my teaching with the mantra "Activity Before Content, Content Before Vocabulary" (ABC-CBV). As we approach the end of a unit I expect students to be explicit in their use of key words and communicate their ideas with clarity and precision.
If this lesson follows a series of labs such as the ones I've placed in this unit, I think you will be surprised how much your students know and can tell you about the bird.
Please familiarize yourself with how the bird works. I have included some readings in the resources below that you should find helpful. Use these to guide your questioning of students and push their thinking.
In particular, I like the following list of questions and investigations:
Q. Is this an example of perpetual motion?
A. No. The cycle repeats itself only as long as the water evaporates from the head.
Q. What is needed in order for the Drinking Bird to work?
A. A difference in temperature between the head and body.
- Observe the operation of the Drinking Bird and explain how it works.
- Discover a way to make the Drinking Bird cycle faster.
- Predict what will happen if a fan blows air toward the Drinking Bird. Does it make a difference which direction the air blows?
- Predict the result of using warmer or cooler water in the glass.
- How long will the bird cycle without needing a refill of the water in the open container? Can you find a way of causing the bird to cycle longer?
Here are two of my students reasoning through the system by breaking the observation into events, and attaching reasons to those events. Note as students explain their thinking and identify the parts of the system and the cycles they include key vocabulary that was not present at the beginning and address some of the ideas they recorded on the sticky notes.
There are 11 steps* to the cycle are as follows:
- The water evaporates from the felt on the head.
- Evaporation lowers the temperature of the glass head (heat of vaporization).
- The temperature decrease causes some of the dichloromethane vapor in the head to condense.
- The lower temperature and condensation together cause the pressure to drop in the head (by the ideal gas law).
- The higher vapor pressure in the warmer base pushes the liquid up the neck.
- As the liquid rises, the bird becomes top heavy and tips over.
- When the bird tips over, the bottom end of the neck tube rises above the surface of the liquid.
- A bubble of warm vapor rises up the tube through this gap, displacing liquid as it goes.
- Liquid flows back to the bottom bulb (the toy is designed so that when it has tipped over the neck's tilt allows this), and pressure equalizes between the top and bottom bulbs
- The weight of the liquid in the bottom bulb restores the bird to its vertical position
- The liquid in the bottom bulb is heated by ambient air, which is at a temperature slightly higher than the temperature of the bird's head.
(*From the Drinking Bird described on Wikipedia.)