laboratory design

Separation and Choices

I allowed my students to choose between two separation type laboratories. About two thirds of the class chose to separate the flavoring out of a grape of cherry soda. The rest of the students used paper chromatography to determine if red-40 dye was in a specific type of candy.

A Class Discussion on the Nature of Science

The first chapter of every middle and high school science textbook I have ever seen contains an oversimplified section on “the scientific method.” I wanted my students to gain an understanding of science by doing science, as best as we can replicate in a classroom, though inquiry labs, class discussions, and defending claims with evidence.

Compiling Student Data

To assist in grading the lab results for this and other quantitative labs that we did, I created Excel spreadsheets where the students’ results could be entered. The spreadsheet then did all the required calculations and compared the students’ results to the theoretical value. This made grading the lab reports much quicker and more accurate, flagged incorrect student calculations, allowed a much more complete discussion of the lab results and permitted “what if” questions to be discussed.

Give Me Back My Copper! A Simple, but Multi-Faceted Lab Activity to Review Lab Skills in Week One of AP Chemistry

In the lab, students are given a 1.5 gram samples of copper. The copper is taken through a series of five chemical reactions ending with the precipitation of solid copper. After the five reactions, students are asked to return their 1.5 gram samples of copper to the teacher.

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.