Lesson Plan

Temperature and Heat

One lesson plan I eagerly look forward to presenting is one that examines the concepts of temperature and heat during energy transfers. I essentially present two materials that possess very different specific heat capacities (e.g. aluminum vs plastic) and ask my students to predict the temperatures for each material. Because of the differing specific heat capacities, students perceive differences between them in terms of coldness, which would lead most people to think that the materials have different temperatures. However, these materials counter-intuitively have the same temperatures, and the reasons why are the crux of this lesson.

To further highlight the main point, I plan to give my students ice cubes to place on these materials and have them hypothesize, and then observe, which ice cube would melt more or less quickly. Students would intuitively think that the ice cube would melt less quickly on what feels to be a colder object (the object with a lower specific heat capacity), but the ice cube will actually melt more quickly on the seemingly colder object, because it conducts heat more efficiently.

Throughout the lesson, my students would be utilizing the scientific method by: (1) creating hypotheses; (2) observing what occurs and collecting data to test their hypotheses; (3) interpreting their observations and data; and (4) communicating their results and conclusions. Students would be recording steps (1) to (4) in their respective notebooks, which would be examined throughout the lesson as a means of formative assessment, and at the end of the grading period as a means of summative assessment.

By the end of this lesson, students will be able to:

Use the kinetic theory of matter to demonstrate how energy is transferred and how phase changes occur
Explain the differences between temperature and heat
Explain how the perception of hot or cold is related to temperature

Inspiration for this lesson plan is credited to Veritasium and the American Association of Chemistry Teachers.

CNSI Measurements at the Nanoscale

Using videos, poinsettia plants, and hand sanitizer in person, I would present examples of hydrophobic surfaces (water rolls off poinsettia leaves very easily) and then ask students to explain why this phenomenon is occurring if they can. I may ask students to write down their initial explanations in their notes. Based on their responses, I would further highlight and then define the following concepts in a brief google slide presentation: the lotus effect, hydrophobicity, hydrophilicity, contact angle, and surface wettability. Afterwards, I would highlight the real world applications of these terms and ask students to suggest other possible applications.

Now that students are primed on what the main topics of the activity are, I would provide students with directions on what they would be doing: manipulating copper pennies (increasing surface area and/or coating pennies with various chemicals like silver nitrate, MUO and DCT) to create superhydrophilic, hydrophilic, hydrophobic, and superhydrophobic surfaces. The bulk of this activity consists of manipulating several pennies as a group to create surfaces of different wettability, after which, we would compare results and then rationalize why exactly these surfaces had become so hydrophobic or hydrophilic.

I would ask students to reiterate upon their initial explanations regarding our original phenomenon (why water rolls off poinsettia leaves so easily) and provide clarity as needed. The reason why these surfaces are have such different surface wettability isn't related just to the chemicals applied (I would discuss the chemistry of these chemicals as applicable) but specifically to the surface areas of the pennies, some of which were roughened on a nano scale. After students have demonstrated understanding on the basics of surface wettability, I would further elaborate on other examples of how surface wettability are manipulated in nature and artificially.

This lesson plan is from the California Nanoscience Institute (CNSI) at UCLA.

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