Keep it Cold - Grade 6
Overview
Middle school lessons utilize local phenomenon and are organized by grade bands. By designing instruction around local phenomenon, students are provided with a reason to learn shifting the focus from learning about a disconnected topic to figuring out why or how something happens. #Going 3D with GRC
Lesson - Energy Transfer
Student Science Performance
Phenomenon: An ice cube melts faster when placed directly on the countertop than on a towel.
Gather:
Students ask questions about the causes of the difference in the rate of two ice cubes melt.
Students plan and carry out an investigation to obtain data to use as evidence for the causes of the difference in the rate heat energy is transferred between two systems causing ice to change from a solid to a liquid.
(Teaching Suggestion: This is a good place for students to focus on questions for the causes of the phenomenon. If the investigation is an experiment, questions should focus on designing a fair test for the causes of the difference in the melting rates. Students should focus on changes in the system. Be sure to have students define the systems. Students use the core ideas related to 1) energy flows from objects with more heat energy to objects with less heat energy, 2) matter changes state when sufficient energy added or removed, and 3) heat conductivity is a property of substances and determines the rate heat moves through a substance.)
Reason:
3. Students construct an explanation supported by evidence from the investigation for the causes of the differences in the rate that heat energy is transferred through different substances to cause ice to change from solid to a liquid.
Class Discussion:
Q: How does the heat energy move between the two systems?
Q: Why does the ice cube melt faster when directly on countertop than on the towel?
Q: Which variables need to be controlled in the experiment to have a fair test?
Q: Why does it take energy to change an ice cube into liquid water?
Q: How does the material between the ice cube and countertop affect the rate of heat moves?
Q: How does the evidence you collected to support your explanation of the causes of the phenomenon?
(Teaching Suggestions: The discussion should focus on students making sense of the transfer of heat energy between two systems. The ice cube is one system and countertop is the other system. They will compare this change to the rate of transfer of heat between the ice cube and the towel on the countertop which are two new systems. The students should call on evidence from their experiment and discuss the transfer of energy at different rates based on the number of layers of paper towels, or the type of material being used. There will be some discussion of “cold” moving. Work with students to help them understand that heat moves, what we perceive as cold is the rate heat moves from our body to objects at lower temperatures.)
4. Students revise their explanations in light of new evidence from the discussion of the causes of different rates that the two ice cubes change from a solid to a liquid.
Communicate Reasoning:
5. Students use two models to communicate differences in the transfer of heat energy between two systems (countertop and ice cube) causing ice to change from a solid to a liquid.
(Teaching Suggestions: Ask students to individually draw and label the model. The movement of energy is key to performance. This Communicating performance may be used as a formal formative assessment. Students should show energy moving from the countertop to the ice more quickly for the ice directly on the countertop and more slowly when on the towels. Student models should capture the idea the heat moves from where there is more to where there is less and that heat moves more quickly through some substances than others depending on properties of the substance.)
Engineering Challenge
Engineering Challenge: Design and build a device capable of keeping ice frozen overnight.
Gather
Students define the problem of how to design a device to keep ice cold or to keep water hot.
Stdents obtain information about how the structure of insulators and conductors of heat function to slow or speed the transfer of heat.
(Teaching Suggestions: A familiarity with basic concepts about heat energy and the relationship between heat and temperature. Heat is a measure of energy and is measured by the mass of matter that changes temperature. Students need a good understanding of thermal energy, heat and heat transfer, including the concepts of conduction, convection, and insulation. Try to help students understand that cold is not transferred, only heat. Students should know how to acutely read thermometers and record data. Students work in teams to design a device to either prevent ice from melting or to keep hot water hot.
Challenge Limitations - The total mass of the materials used cannot exceed ________ grams (e.g., the total mass of materials used can not exceed 100 grams or 200 grams). The teacher decides on the mass. The students select different materials that do not exceed the set mass and build a device. The mass includes the materials the student use to hold the device together (e.g., glue, tape, string).
Challenge Criteria: Build a device to keep ice frozen or hot liquids hot for as long as possible.
Reason
Students design and build a device to slow the transfer of heat energy into or out of a system.
Students develop a model to show the transfer of heat energy into and out of the system of their device.
Class Discussion:
Q: Why do people like cold drinks on a hot day?
Q: How do you keep a cold drink cold and a hot drink hot?
Q: Which direction does heat flow in the device you build?
Q: How does heat move through a material?
Q: What are the properties of good insulators?
(Teaching Suggestions: Over the years, engineers have spent a lot of time trying to come up with creative ways to keep some things hot and other things cool. Today, we are going to act as if we are engineers and explore ways to keep something hot. Show demo-blocks and ice Show video- http://www.abc.net.au/catalyst/stories/3296880.htm Video )
Communicate Reasoning
5. Students construct an explanation for how their device changed the rate of heat energy transfers into or out of the system.
*See attached document below for full lesson.
Additional Lessons can be found at #Going 3D with GRC (Gathering, Reasoning and Communicating). Original authors were: Erin Finlay and Zulainny Perez, and Chiefess Kamakahelei.