Adding acidic ingredients is an important way to protect foods from dangerous toxins produced by organisms like C. botulinum, a microbe that is common and harmless in the environment but deadly when sealed with food in a jar. In the lab, testing the pH of a substance (how acidic or basic it is) provides important information for ensuring food safety. This module introduces users to proper sampling techniques when testing pH and explains how adjusting a food’s acidity can keep it safe from C. bot. Virtual Labs – Acidifying Salsa familiarizes the user with food science lab equipment and teaches standard techniques for sampling. The interactive animation guides the user through theory and practice of adjusting pH, so they will have familiarity with the equipment and procedures when encountered in a real lab.

Interactive online tutorial about growing urchin larvae in a lab setting. Students manipulate data and are led through a lab-based situation. There is a module on ocean acidification. Lesson plans can be downloaded from website.

The aim of this lesson is to introduce the concept of Neutralization and its application in our daily lives. Students are encouraged to construct their knowledge of Neutralization through brainstorming sessions, experiments, and mind mapping. This video lesson presents a series of stories relating to Neutralization—beginning with a story of a girl being cured from a stomach ache with the help of Neutralization. Prerequisites for this lesson are knowledge of the basic concept of Neutralization, chemical equations and the pH indicator scale. The lesson will take about 50 minutes to complete, but you may want to divide into two classes if the activities require more time.

Interactive log p-h diagram for displaying refrigeration cycles of different refrigerants.
Automatic calculation of the COP for heat pumps and refrigerators. Free online tool, no registration required.

More detailed information:
The thermodynamic state of a fluid (e.g. the refrigerant R134a) can be represented in state diagrams as a single point. Complete processes such as refrigeration cycles are visualized by connecting points with lines. These connecting lines correspond to changes in the state of the fluid.

In refrigeration technology, the pressure-enthalpy diagram is by far the most frequently used state diagram. The pressure is mostly scaled logarithmically, hence the name log ph diagram.

The thermodynamic properties of a refrigerant are represented in the state diagram as lines of constant state variables - so-called isolines.

Test the pH of things like coffee, spit, and soap to determine whether each is acidic, basic, or neutral. Visualize the relative number of hydroxide ions and hydronium ions in solution. Switch between logarithmic and linear scales. Investigate whether changing the volume or diluting with water affects the pH. Or you can design your own liquid!

Test the pH of things like coffee, spit, and soap to determine whether each is acidic, basic, or neutral. Visualize the relative number of hydroxide ions and hydronium ions in solution. Switch between logarithmic and linear scales. Investigate whether changing the volume or diluting with water affects the pH. Or you can design your own liquid!

This lesson explains the way pH can influence nutrient uptake and absorption in plants, and includes a lab activity to test soil samples.  Lesson and activity from Nebraska CASE Soybean Curriculum.