# Change, Constancy & Measurement

## 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.

## 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.

## 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.

## The Sweeter Side of Density

In this Activity, students determine the density of different sugar solutions (0-50%). They then dye the solutions and devise a method to combine the solutions to make a multi-colored, layered heterogeneous mixture. This Activity could be used in units dealing with measurement or density.

## 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.

## 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.

## How Heavy Is a Balloon? Using the Ideal Gas Law

In this Activity, students explore buoyancy with helium-filled Mylar balloons. They use the ideal gas law to predict the mass of the balloon if it were empty, compare it to the actual mass of the empty balloon, and discuss experimental sources of error. This Activity demonstrates the ideal gas law and introduces students to the concept of buoyancy.

## 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.

## Popcorn: What's in the Bag?

In this Activity, students investigate microwave popcorn, the process of microwave-promoted popping, and the materials involved: water, vegetable oils, starch, and special packaging materials. This Activity supports discussion of thermal and electromagnetic energy, phase changes, intermolecular forces, patterns of solubility, and the structure of fats, oils and starches.

## I Screen, You Screen, We All Screen for Phenolics

In this Activity, students use a colorimetric visualization test to screen grape juice for phenolic content. Students use the test to examine differences in phenolic content of juices prepared with different processing methods. Most of the materials are readily available at the supermarket.