# Evidence, Models & Explanation

## Applying Modeling Instruction to High School Chemistry To Improve Students’ Conceptual Understanding

Larry Dukerich has been using Modeling Instruction for many years. He is a founding member of the AMTA.

## Colors in Liquid Crystals

In this Activity, students investigate the relationship between temperature and composition and the reflected and transmitted colors of a common nanoscale material, the cholesteric liquid crystal.

## Hold the Heat: Global Warming and Calorimetry

In this Activity, students perform quantitative calorimetric measurements on samples of ice/water heated by incandescent light bulbs and/or convection with room-temperature surroundings. They measure and graph temperature as a function of time.

## Memory Metal

In this Activity, students compare the properties of nitinol metal wire (known as "memory" metal) and ordinary wire. Using the observed properties, they design (and possibly make) a toy that would use memory metal to operate. This Activity connects toys with science, and allows students to become inventors as they design a toy of their own.

## A Candle in the Wind

In this Activity, students investigate physical changes that occur in a candle to learn how a candle functions and how you can blow it out. This Activity is based on a series of lectures presented by Michael Faraday in the 1850s.

## Mass Spectra

In this Activity, students solve puzzles that are analogous to finding the amino acid sequence of a peptide using mass spectrometry. Students identify words that have been broken into letters or groups of letters. In many textbooks instrumental analysis and various types of spectrometry are mentioned only in passing.

## Modeling Dynamic Equilibrium with Coins

This Activity explores factors that influence dynamic equilibrium, including how long it takes two populations to equilibrate, and the relative amounts of reactants and products present at equilibrium. Students first use concrete objects (coins), then progress to mathematical calculations of equilibrium without physically manipulating the objects.

## Fun with Fingerprints: Cyanoacrylate Fuming

In this Activity, students develop fingerprints using the cyanoacrylate fuming method on different types of surfaces. They investigate the technique’s effectiveness and test the effects of changing the temperature and humidity of the fuming chamber.

## Flipping Pennies and Burning Candles: Adventures in Kinetics

In this Activity, students collect data to determine whether two processes, flipping pennies and burning small birthday candles, follow zeroth- or first-order rate laws. Students first collect data on the number of pennies remaining "heads up" after several successive tosses and then measure the mass of a burning candle over time.

## Soil Testing: Dig In!

In this Activity, students collect soil samples and characterize them by examining their physical appearance, water holding capacity, sedimentation, and pH. Based on their observations, they can see that different samples of something as universal as soil can be quite different from each other. This environmental chemistry Activity can be used to complement a celebration of Earth Day.