Can You Keep Ice From Melting?
During this investigation, you are going to explore how ice melts. You will be exploring the testable question, “Can I affect the rate at which ice melts?” To do this, you will make some predictions about what makes a good insulator or what would slow the rate of ice melt. Using a control, you will record the rate at which your ice cube melts. You will be comparing your findings with the findings of others in the class. Following the inquiry, you will draw conclusions about insulators and give an explanation for why the control was important for this experiment.
Allow a planning session that will take 15-30 minutes. (I gave a prompt as a homework assignment the night before.) Prepare containers (5-10 minutes); wait for ice to melt (1/2 day or more); write-up (15-30 minutes).
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Task Write Up
This activity requires little advanced preparation and minimal materials. A yogurt cup for each student and one for the control, ruler, ice cubes, (approximately the same size), and the materials the student chooses to use as insulation, brought from home. For students who do not bring in materials, you might have various types of cloths, paper, plastic, Styrofoam packing peanuts, etc., on hand.
The students were exposed to the scientific method earlier in the year and have continued to build upon their understanding through various testable situations. This task solidified their understanding of the value of control in experimentation. With the tangible example of the melting ice, they had something concrete with which to compare their findings. The focus was not so much on learning about insulation as on the skills of recording information and comparing results. Their results and comments gave me an assessment checkpoint to understand their knowledge of the scientific process as well as their ability to accurately record information and draw conclusions.
This investigation task is a good opportunity to apply the scientific method. It allows the teacher to assess the students' grasp of science terms associated with the scientific method. The following aspects of the scientific method are included in this activity: testing a hypothesis based on a prediction, collecting and recording data, comparing findings to a control, and analyzing data to draw conclusions.
Students will be given an 8-ounce yogurt cup. As a homework assignment the night before, they are given the prompt: “Design a good insulator, that would fit in your cup, that would keep ice from melting.” The students are then instructed to come to school the next day prepared to experiment. To begin the experiment the students take a few minutes to prepare their cup. Students are then instructed to measure and record the size of their ice cube and the control cube. The control cube is placed in the yogurt cup without any insulation. The cups are then all placed in the same area of the classroom. The sizes are checked at regular intervals. When the experiment is over (i.e.: cube melts, control melts) the students take time to draw conclusions from their observations.
The write-up includes four questions:
- What makes a good insulator?
- What were not good insulators?
- Why is the control important?
- What would you choose if you were to do the experiment again?
We did this experiment during a mini-unit on the Polar regions of the world. We also learned about glaciers, icebergs, ice shelves and ice sheets. We were also able to cover a bit of earth science as we learned about the tilt of the earth and why the polar regions are so cold.
Many children’s books compare the two polar regions or cover exploration and adventure in Antarctic and the Arctic. Students could also write their own books comparing these regions.
It is optimum to have the experimental ice cube and the control ice cube be the same size. For some students ready for a mathematical challenge, however, I gave them ice cubes of different sizes. Those students calculated the rate of melt by the use of simple ratios.
As another interdisciplinary link the students used a Venn diagram, comparing/contrasting the animals of the Arctic with those of the Antarctic.
-Understandings about the Nature of Science (see appendix)
Keep the ice cold until ready to use. If the ice is allowed to melt a little bit before it is used, it tends to clump together, causes chips, and cracks when you pull it apart. Students should also label their yogurt cups in advance.
Some guiding questions could include:
- What is your prediction? What question are you trying to answer?
- Where should we place the cups after putting the cube in them?
- Should we put all the cups in the same spot? Why or why not?
- What will make this a fair test?
- Should we check on the cups at certain times? Why or why not?
- Do you think you chose a good insulator? Why or why not?
- What would you change next time, if anything? Why would you do so?
(Unifying concepts/big ideas and science concepts to be assessed using the Exemplars Science Rubric under the criterion: Science Concepts and Related Content)
Mathematics: Students determine the patterns and/or which kinds of change are happening by making a graph or a table of measurements (change and constancy). Students understand that representing and analyzing data appropriately, identifying trends and patterns and using numerical data and precise measurements in describing events, answering questions, providing evidence for explanations and challenging misconceptions are important in scientific inquiry.
Scientific Method: Students observe and explain reactions when variables are controlled (cause and effect). Students see that how a model works after changes are made to it may suggest how the real thing would work if the same thing were done to it and that choosing a useful model (not too simple, not too complex) to explore concepts encourages insightful and creative thinking in science, mathematics and engineering (models).
Physical Science – Properties of Matter: Students observe and compare physical properties of matter.
Design Technology – Constraints and Advantages: Students observe that some insulators are better at keeping ice from melting than others. Students identify the characteristics of a specific property to determine if it would make a good insulator.
Students should be able to determine what materials made better insulation by comparing melt times (some of the classroom’s best included snow and newspaper). Students show their understanding of the term control throughout the experiment by explaining its importance in relationship to this inquiry. The student should be able to explain that it is necessary to compare the melt time of an ice cube in an insulated cup with the melt time of a cube in a cup without insulation to determine if the insulation is effective. The student should also be able to determine what s/he might do differently next time. Some students may think of something new they would like to test that wasn’t tried during the inquiry.
This student’s solution is lacking in detail and shows little understanding of what would make a good insulator. S/he also states that the cube will last longer in a colder spot, despite being told that all the cups would need to remain in the same spot. The student’s data are recorded, but units are not labeled. There are no conclusions drawn from the data. The task is incomplete.
This student’s work shows that s/he was able to understand the purpose of the inquiry and the use of control. The hypothesis, “I think mine will be bigger than the control piece of ice because mine has a good seal,” demonstrates some understanding; however, the student then states, “If it’s a good insulator then it might melt faster or slower,” which is confusing at best. The statement, “Control is so you can find out if your insulator works,” is a brief response showing some understanding. When the student comments on what s/he would do differently, it is not clear what materials the student is referring to (“all the insulators I thought of”) – evidence that the student is not using data to draw conclusions.
This student’s solution is complete. In the hypothesis, the student gives a reasonable explanation of which cube will last longer and why s/he believes it will be larger. Measurements are precise (although numerals should be used), units are labeled, and all data are recorded correctly. Conclusions are based on data collected and show evidence that the student understands the purpose of using a control.
This student’s solution is complete, accurate and detailed. In the hypothesis, the student gives a reasonable explanation of which cube will last longer and why s/he believes it will last longer (“paper towels will slow the process of melting an ice cube”). Measurements are precise, units are labeled, and all data are recorded correctly. Scientific terms are used appropriately.