# Science as a Human Endeavor

## 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.

## 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.

## Chemistry of Cement

In this Activity, students use a commercial cement mix to produce concrete. They investigate how changing key variables such as concentrations, curing temperatures, and the addition of various substances affects properties such as setting time, hardness, and plasticity.

## 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.

## Bowling for Density!

In this Activity, students predict whether a given bowling ball will float or sink in tap water. Students design a procedure to collect radius and weight measurements to calculate the density of their ball. They then test their prediction by placing the ball in a large container of water, which yields the surprising observation that some bowling balls do float.

## Whatever Floats (or Sinks) Your Can

In this Activity, students test whether cans of carbonated beverages sink or float in water and then determine whether caffeine content, soda color, or sugar content in the carbonated sodas is responsible for the buoyancy of the sealed cans. This Activity can be used as an introduction to density in a middle school physical science course, or a high school chemistry or physics course.

## Nanopatterning with Lithography

In this Activity, students learn the general principles of serial and parallel nanofabrication techniques. Students use nylon spheres, contact paper, and talcum powder to form patterns. Using this macroscale analogy, students explore the parallel fabrication technique known as nanosphere lithography.

## Calories - Who's Counting?

In this Activity, students determine how many calories are released per gram when marshmallows and cashews burn and then compare the quantity of energy available from carbohydrates versus fats. Students burn the food items beneath a metal soft drink can containing water and measure the resulting change in temperature of the water.

## A Kool Reaction from the Fine Print

In this Activity, students gain an understanding of the importance of reading reagent labels both in chemistry class and on consumer products. Students explore the chemistry behind the directive on a package of Kool-Aid "Do not store in a metal container". The Activity illustrates properties of acids and metals.

## Color My Nanoworld

This Activity introduces students to the unique properties of nanoscale materials through exploration of size-dependent optical properties of gold nanoparticles. Students first prepare a solution of gold nanoparticles. They then investigate the solution’s use as an electrolyte sensor by adding a non-electrolyte and a strong electrolyte, and observing any resulting color changes.