# Understanding About Science and Technology

## 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.

## 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.

## Pondering Packing Peanut Polymers

In this Activity, students compare polystrene and cornstarch packing materials ("peanuts"). Both are made of polymers, but because of their composition, they behave very differently in various solvents. Students extrapolate how these differences in behavior relate to environmental effects, such as filling landfills with non-biodegradable materials.

## Checkerboard Chromatography

In this Activity, column chromatography separations are simulated using a grid, colored paper squares, and a six-sided die. Students observe the effects of changing flow rate, column length, and mobile phase composition. As squares come off the grid, the separation (or lack thereof) of the colors is noticeable.

## Determining Rate of Flow through a Funnel

In this Activity, students make funnels using plastic beverage bottles and rubber stoppers with differing numbers of holes or sizes of holes. They then determine the rate of flow of water through the funnels and identify factors that affect the rate of flow. This Activity uses easy-to-observe phenomena that model a chemical reaction with an identifiable rate-controlling step.

## Investigating the Invisible: Attenuation of Radio Waves

In this Activity, students investigate properties of radiation using a handheld radio. Students compare the abilities of conductive and dielectric materials to attenuate or block, radio waves, and compare the attenuation of AM versus FM radio waves. The radio is placed inside different objects and students record which materials blocked or attenuated the waves.

## 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.

## Cool! Rates of Heating and Cooling

In this Activity, students measure the rate of warming for a chilled thermometer bulb held in room temperature air, for a chilled bulb held between two fingers, and for a few milliliters of ice-cold water. Students discover that the warming process is not linear. This Activity emphasizes the importance of measuring temperature change and its relevance to other experiments.

## How Does Your Laundry Glow?

In this Activity, students examine the effect of pH on the intensity and color of the emission of fluorescent dyes in liquid laundry detergent. They perform two titrations using vinegar to estimate the pH at which the fluorescence properties change. In the second titration, sodium bicarbonate is added to buffer the detergent solution.

## Fluorescent Fun: Using a Homemade Fluorometer

In this Activity, students investigate the fluorescence of highlighter marker ink and the principles employed in studying fluorescent molecules using a homemade fluorometer and different colored filters.