The pH of Solution

The model visualizes the concentrations of H3O+ and OH- at different pH levels. It helps to address four common misconceptions on the pH of solution. It also provides the pH values of a collection of common items.


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Titration of acid with a strong base

This model presents the differences in titrating a strong acid (HCl) and a weak acid (Acetic acid). Students are able to observe the changes in pH when titrating a strong/weak acid with NaOH solution. Students may also change the concentrations of acids and the titrant and observe the corresponding results. 


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Titration of base with a strong acid

This model presents the differences in titrating a strong base (NaOH) and a weak base (Ammonia). Students are able to observe the changes in pH when titrating a strong/weak base with a HCl solution. Students may also change the concentrations of bases and the titrant and then observe the corresponding results. 


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Buffer Titration

How does a buffer behave differently from a strong acid or a strong base during titration? Check this model. Starting at the same pH level, see how much more titrant is needed to cause a significant pH change.  


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Dissolved Inorganic Carbon in a closed system

Carbonic acid (H2CO3), Bicarbonate ion (HCO3-), and carbonate ion (CO3 (2-))are three species of dissolved inorganic carbon (DIC) that coexist in water. In a closed system, assuming that no carbon leaves or enters the system, the proportions of these species are determined by many factors. This model presents the proportions of three DIC species at different pH levels, ranging from 0 to 14, holding other factors constant. This model may serve as the foundation for students to explore the phenomenon of ocean acidification.


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Ocean Acidification

Today's average ocean pH has dropped from 8.2 to about 8.1 as the ocean has taken up a large amount of CO2 from human activities since the industrial revolution. Many students are confused by the change in carbonate ion concentration in the ocean resulting from the increase in oceanic CO2 uptake. This model provides students with an established oceanic carbon system. Students may uncouple the three reactions involving the changes in three inorganic carbon species and recognize the long-term system dynamic to develop a deep understanding of these changes.

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Watch the YouTube Tutorial

States of Matter-Basics

This model represents the changes of state at the micro-particle level. By heating up and cooling down a set of particles, students can explore the fundamental features of three states. This model is particularly good for students to identify visual evidence for describing different states and the changes,  and explore the relationships between particles’ kinetic energy and the space they may take.


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States of Matter-Intermolecular Forces and Kinetic Energy

This model represents the changes of state at the micro-particle level. In this model, the states of matter are determined by three factors–kinetic motion, attraction and repulsion. By heating up and cooling down a set of particles, students can explore the fundamental features of three states. This model also allows students to explore the interplay between the attractive force and repulsive force. This model is particularly good for students to identify visual evidence for describing different states and the changes, as well as explore how the states of matter are influenced by intermolecular forces and the kinetic energy.


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This model simulates the state changes of water. By heating up and cooling down the water molecules in the model, you add to and remove the kinetic energy from the molecules. Due to the intermolecular forces, these water molecules will then take more or less space. When they are cooled down enough, these molecules will form a crystalized structure, i.e.,ice. This model can be used to explore the states of water, the relationships between molecules’ kinetic energy and space they may take, and the unusual space changes in water when it freezes.


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