Teachers and families across the country are facing a new reality of providing opportunities for students to do science through distance and home learning. The Daily Do is one of the ways NSTA is supporting teachers and families with this endeavor. Each weekday, NSTA will share a sensemaking task teachers and families can use to engage their students in authentic, relevant science learning. We encourage families to make time for family science learning (science is a social process!) and are dedicated to helping students and their families find balance between learning science and the day-to-day responsibilities they have to stay healthy and safe.
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Sensemaking is actively trying to figure out how the world works (science) or how to design solutions to problems (engineering). Students do science and engineering through the science and engineering practices. Engaging in these practices necessitates students be part of a learning community to be able to share ideas, evaluate competing ideas, give and receive critique, and reach consensus. Whether this community of learners is made up of classmates or family members, students and adults build and refine science and engineering knowledge together.
We've probably all experienced the phenomenon of stepping from a carpeted floor to a bare floor and noticing our feet feel colder. (If you haven't noticed, give it a try!) Did you ever stop to wonder how two floors in the same home (on the same level or story) could feel like they were at two different temperatures?
Today’s task, Why does the ice melt faster?, provides an opportunity for students and their families notice and wonder about a related phenomenon - ice cubes melting at different rates on two different household objects from the same room in the house. Students engage in science and engineering practices to make sense of science ideas energy is spontaneously transferred out of hotter objects to colder ones and when two objects interact, energy can be transferred from one to the other through collisions (even when those objects are molecules).
Today’s task builds on science ideas students make sense of in Tuesday's (April 14) Daily Do, Why are the temperature changing?
Guidance: Students will observe the phenomenon through the Amazing Ice Melting Blocks video (see above). An ice cube is placed on each of two blocks that appear to be similar and students observe what happens throughout the time-lapse video. The goal is for students to generate questions that can be investigated with materials found at home. Using evidence from data collected in those investigations, students develop a model to explain their observations of the ice on each of two blocks.
Presenting the Phenomenon: Ask students to watch the video and to complete a see-think-wonder chart, as shown below. Students should record observations (“I see…”), possible explanations of the phenomenon (“I think…”), and questions that they would like to investigate (“I wonder…”). It may be helpful to watch the video multiple times and to revisit the see-think-wonder chart. Students can print the See-Think-Wonder table or record their ideas on blank paper using the table below as a guide.
You can use the following question to prompt students’ thinking as they view and process the video.
What did you see happening in the video?
What is causing the ice to melt?
Why do you think the ice melts faster on one block than the other?
What do you think is the same or different about the blocks?
What questions do you have?
Guidance: In the absence of melting blocks, students will use household materials to help them figure out why the ice melts faster on one block than the other. Listed below are two groups of common kitchen objects. Before guiding students to select one object from each group, ask them to think about what the objects within each group have in common and what the differences are between the two groups.
Metal cookware - pots, pans, cookie sheets, baking pans, etc. made from copper, cast iron, aluminum, steel, or nonstick-coated metal
Metal mixing bowl
Non-metal cookware - cookie sheets, baking pans, etc. made from glass, ceramic, stoneware, or silicone.
Cutting board - plastic or wood
Countertop - stone, wood, concrete, or laminate
Bowls or plates - plastic, glass, or ceramic
Wax paper or parchment paper
One object selected from Group A
One object selected from Group B
Ice cubes of similar size and shape
Towel or paper towels
Thermometer (optional) A surface thermometer (infrared or liquid crystal strip) would be ideal, but a meat thermometer could also be used. If you have a thermometer, make sure it can measure room temperature (some meat thermometers can't measure temperatures this low). Don’t worry if you don’t have a thermometer.
Share these procedures with your students.
Select 1 object from Group A and one object from Group B.
Print the data table or copy the table below onto blank paper. Include the name of the objects you selected from Group A and B.
If you have a thermometer, record the room temperature.
Touch each object and record how they feel to the touch. Do one object feel “warmer” or “cooler?”
If you have a thermometer, record the temperature for each object. This where a surface thermometer would be ideal. If you only have a meat thermometer, place the tip in direct contact with the surface of the object and record the temperature. What do you notice about the temperature of the objects compared to how they felt to the touch? Keep this in mind as you make your predictions and try to explain your results. If you don’t have a thermometer, think logically about the temperature of each object. Assuming they have been stored in the open or in a kitchen cabinet, how should their temperatures compare to room temperature? Is there any reason for them to have different temperatures?
Make a prediction about which object will cause the ice to melt faster and which one will cause the ice to melt slower.
Take out of the freezer one ice cube for each object you are testing. Select ice cubes that are as close as possible to the same size and shape.
Place one ice cube on each object and start a timer or record your starting time.
Observe the ice cubes and record how long it takes the cube to melt on each object.
Making Sense of the Investigation: Use the following prompts to help students make sense of the investigation.
What patterns did you observe? (ice seems to melt faster on metal objects than on nonmetal objects, ice seems to melt faster on objects that felt “cooler” to the touch, the starting temperatures of the objects were the same, etc.)
How did these patterns compare to your predictions?
How do these patterns help you explain why the ice melts faster on some objects than on others?
What do you think might be happening at the microscopic level that would help you explain the patterns you observed?
You can find additional prompts in STEM Teaching Tools Practice Brief 41: Prompts for Integrating Crosscutting Concepts Into Assessment and Instruction.
Ask student to think about what causes ice to melt and why it might melt faster on some materials than others. Then ask them to develop an initial model to explain why the ice melted faster one object than another object. Share the model scaffold with students or ask them to refer to the scaffold pictured below and draw their initial models on blank paper.
Consider using the following guidance to support students in developing an initial model to explain their observations in Investigation 1.
Remind students their models don't need to be perfect - they will have a chance to revise them after collecting additional evidence.
Guidance: Investigation 1 allowed students to experience and explore the ice melting phenomenon first-hand. Investigation 2 engages students with an investigative phenomenon that will help them make sense of heat and how it moves. Students will investigate the phenomenon of placing two spoons, one metal and one nonmetal, into a mug of hot water. You can prompt students’ thinking about heat and its movement by using the “Hot Spoons” formative assessment probe. This probe is based on the “Cold Spoons” probe from Uncovering Student Ideas in Physical Science, Volume 3 and on the “Hot Spoons” task from Predict, Observe, Explain: Activities Enhancing Scientific Understanding. You can learn more about using formative assessment probes by reading the “Why is my shadow always changing?” Daily Do. The probe and investigation are best used in three steps.
Microwave (Alternatively, you can use a kettle or small pot to heat water on a stove or an electric kettle.)
Plastic or wooden spoon
Optional: Thermometer - A meat thermometer or a surface thermometer would work equally well for this investigation. And again, don’t worry if you don’t have any thermometer, at all.
Safety Note: Students will be working with hot water at a temperature similar to hot chocolate. Adult supervision and careful handling should be employed to reduce the risk of burns.
Share the “Hot Spoons” probe with your students. Read through the probe with students or give them time to read through it. Have students share their initial answers and reasoning. If you are working with multiple students, it might be helpful to have them write down their initial responses before sharing. Prompt students to clarify their thinking, but be careful not to give away the explanation at this point.
Tell students, “We are going to try this out, but with a twist. The five friends were using metal spoons, but we are going to compare metal and nonmetal spoons in hot water. How do you think a plastic or wooden spoon would compare to a metal spoon?” Have students share their predictions.
Gather the materials and have students create a table like the one below to record their predictions and observations. You can also use the printable data table provided in the resource collection.
As students make their initial observations, you will need to call their attention to one of the surprising aspects of this phenomenon. Students should have noticed that metal objects consistently feel “cooler” than nonmetal objects like the plastic/wooden spoon. If you are using a thermometer, then now is a good time to call students’ attention to the fact that the room temperature and the temperature of both spoons are all the same. Prompt students to think about why the metal spoon feels cooler if it actually is the same temperature as the plastic/wooden spoon. If you do not have a thermometer, then you will need to guide students to think through the scenario logically. You might use the following script. Let’s think about the temperature of the spoons. What is the temperature in this room? Let’s look at our thermostat. It says the room is 72 degrees. Where have the spoons been? Has either of the spoons been heated or cooled? So, what must be the temperature of both spoons?
Have students record their initial observations and predictions.
If you have a microwave available, then microwave 6 ounces of water in a microwave-safe mug for 90 seconds. The water will be near boiling, so use caution in handling the mug of hot water.
Have students place the two spoons into the hot water and let it sit for 5 minutes.
After 5 minutes, students should record their final observations.
Making Sense of the Investigation:
Use the following prompts to help students make sense of the investigation.
What patterns do you observe in the data from both investigations? (both objects were the same starting temperature but one felt colder than the other, the objects that felt cold had/caused the biggest changes - fast melting ice cube/highest temperature change)
Why do you think the metal spoon warmed up faster than the plastic/wooden spoon? What might be happening at the microscopic level that helps us explain this?
How does this help us understand the ice melting investigation? How does the energy flow in this investigation compare to the energy flow in Investigation 1?
Revisit the “Hot Spoons” probe. Give students time to reread and respond to the probe. Then have students share their responses and thinking. At this point, you want to press students to use evidence from the investigation to justify their explanations. If a student is committed to an explanation other than Jamal’s, then press them to revisit the evidence from the investigation.
The best answer is Jamal’s: “I think heat from the hot chocolate moves through the spoon to my hand.” The second law of thermodynamics puts constraints on how energy flows in a system. Warmer objects transfer energy to cooler objects, not the other way around. Thermal energy from the hot chocolate heats the metal spoon, which is a good conductor, and the energy is then transferred from the spoon to Jamal’s hand. The energy gained from the hot chocolate caused the particles in the spoon to move faster. This energy is then transferred from the spoon to Jamal’s hand as these faster-moving particles collide with the slower-moving particles in his hand. The other answers express common misconceptions about heat and its movement.
Guidance: Now that students have built some direct experiences and begun to wrestle with ideas about heat and temperature, you will want to support them in obtaining and making sense of some scientific information. In order to fully model and explain the ice melting phenomenon, students need to be able to answer the following questions.
What makes something hot or cold?
How do things get warmer or cooler?
To help them answer these questions, engage students in the PBS Learning Media Thermal Energy Transfer interactive module.
You can use the discussion questions from the lesson to help students summarize the new information they obtain from the lesson.
Can you explain why you feel warm when you are standing near a campfire?
Why does a carpeted floor feel warmer to bare feet than tile or wood even though all surfaces are the same temperature?
What information would you need in order to predict whether transfer of thermal energy would occur when two objects or materials interact?
What would happen if a person who is wearing a heavy winter jacket were to place a thermometer inside the jacket next to his or her skin? What would happen if we took the same jacket, after it had been hanging in a closet, and placed a thermometer inside?
Students can learn more by exploring the animations and student reading from the Middle School Chemistry Lesson 2.1 on Heat, Temperature, and Conduction. Students who want to dive deeper into these concepts can conduct online research on the thermal conductivity of common materials.
Guidance: Now, you will want to help students transfer their learning from the investigations and interactive lesson to revise their model of the ice melting phenomenon. You might have students use the following questions to organize their ideas from the investigations and interactive lesson.
Now, prompt students to revisit their models for the ice melting phenomenon.
Think about what causes ice to melt and why it might melt faster on some materials than others. For each object you tested in Investigation 1, revise your initial model to explain why the ice melted faster or slower on that object. Use the zoom-in circles to show what might be happening at the microscopic level that can help you explain your observations. Be sure that you are incorporating ideas from Investigation 2 and from the interactive lesson. You can make changes on your original model or start with a fresh version.
Applying the Model: Why does the ice melt faster?
Revisit the original phenomenon by watching this extended Ice Melting Blocks video. In addition to the original phenomenon, this video shows the initial temperature of the blocks and shows how the blocks interact with heat-sensitive liquid crystal sheets. Students can use this additional evidence to support their explanations. Have students use their models to explain why the ice melts faster on one block than the other, and have them infer the type of material for each block. You can find an explanation of the blocks in the Flinn ChemFax Lesson Plan: Ice Melting Blocks.
NSTA has created a Why does the ice melt faster? collection of resources to support teachers and families using this task. If you're an NSTA member, you can add this collection to your library by clicking ADD TO MY LIBRARY located near the top of the page (at right in the blue box).
The NSTA Daily Do is an open educational resource (OER) and can be used by educators and families providing students distance and home science learning. Access the entire collection of NSTA Daily Dos.