laboratory design

Cookbook to Inquiry....Another Attempt

There is a hydrate lab which is done by many teachers. Typically, students first use a known hydrate and are provided the formula.  As an example, they might use CuSO4 . 5H2O.  On paper, they would work through the percent by mass of water in copper (II) sulfate pentahydrate.  They then would be given a mass of the copper (II) sulfate pentahydrate, calculate how much water they should lose and then they would heat it and compare the data with the calculated value. Next, they are given an unknown hydrate.  They are also given the molar mass of the unknown salt of the hydrate and they have to calculate the molar ratio of salt to water based on their data.  Here is one possible way to “tweak” this lab.

An After-Dinner Trick

In this Activity, students investigate a classic chemistry demonstration that uses the phenomenon of freezing-point depression to lift an ice cube out of a glass of water with a thread. They first test how adding salt, pepper, cream, and sugar to cold water affects the temperature.

Brushing Up on Chemistry

In this Activity, students make their own toothpaste and use various tests to compare its properties with those of commercial toothpaste. This includes testing its ability to remove stains from the dyed shells of hard-boiled eggs. The Activity allows students to discover more about a cleaning product they use every day.