Overview

Background:

PhET was started in 2002 by Carl Wieman, a recipient of Nobel Prize in Physics, to improve "the way science is taught and learned" (Perkins, 2010). PhET started to be a website with simulations mainly for Physics. The site is growing with new simulations added. Now a growing number of simulations relating to Chemistry, Biology, Earth Sciences and Mathematics are added. Simulations or sims are models or imitations of real world processes. Each sim on PhET is developed by a team of scientists, science educators, science education researchers and software engineers. Each sim is then tested through observations of students' use and student interviews (Perkins, 2010).


Classroom Use:

Simulations can be used in a variety of different ways in all grade levels. This blog focuses on using sims for secondary science classrooms. Although it is not limited to any science subject, all the examples given will be mostly related to Chemistry. Sims can be used in different educational settings: lectures, individual or small group activities, lab, and homework assignments. (Details of using sims from PhET for each is under "How to use in the classrooms tab.) PhET sims can be used in teaching to introduce a new topic, build concepts or skills, reinforce ideas or provide final review and reflection (Wieman, 2010).

The developers of PhET highly suggests the use of the simulations in guided inquiry activities. They suggest using the following strategies:

1. Define specific learning goals
2. Encourage students to use sense-making and reasoning
3. Connect and build on students' prior knowledge & understanding
4. Connect to and make sense of real-world experiences
5. Design collaborative activities
6. Give only minimal directions on sim use
7. Require reasoning/sense-making in words and diagrams
8. Help students monitor their understanding

A detailed description of this can be found here.


Classroom Value:

Advantages of PhET sims:
Simulations can be used in the same way as classroom demonstrations and classroom experiments to provide the same benefits. However, the following additional advantages can be obtained (Wieman 2010).

• Simulations can be used when real equipments are not available or impractical to set up
• Simulations can be used for experiments that are impossible to do in real life such as explore the immediate response of adjusting greenhouse gases)
• Independent variables can be easily changed. (figure 1: photoelectric effect)
• Simulations can show invisible and explicitly connect multiple representations. For example, simulations can show molecules for a chemical reaction. It can also connect pressure and temperature relationships for gases. 
• Students can run sims at home to clarify and/or strengthen their knowledge and perform extend experiments. 

More Values:

The PhET simulations are of many different types each showing the concept of the indicated topic well. For example, figure 1 and 2 below shows the Reactions, Rates and Leftovers Simulation. This simulation helps students better understand a chemical reaction using a sandwich analogy. Students can make their own sandwich "chemical reaction equation". For example figure 1 shows that 2 bread + 1 cheese makes 1 sandwich. Values of bread and cheese can be changed. In the "before 'reaction' box, we can see that we have 5 bread and 2 cheese (the amount of each 'reactant' can be changed). Using the "chemical equation" that 2 bread and 1 cheese makes 1 sandwich, we can see that 2 sandwiches can be made with 1 leftover bread. The cheese is the limiting reagent. After students understand how this works with the sandwich analogy, they can apply it to a real reaction such as the one shown in figure 2. Each simulation is unique but valuable. In this simulation we can see that it's valuable in showing a chemistry topic with a real world analogy to help students better understand a chemical reaction. This simulation also has a third tab shown in both figure below: the game tab. This allows students to practice more with an interactive game to help them understand the topic better in a more engaging and interactive way.

Figure 1: Reactants, Products and Leftovers Simulation - Sandwich Analogy

Figure 2: Reactants, Products and Leftovers Simulation - Real Reaction

As we can see from the above example, PhET sims engages students in exploration. The simulations are "flexible tools" that allow students to choose their own path such as creating their own "chemical equation" in the sandwich analogy but still provide constraint so that the students choices are on the right track (Podolefsky, 2010). The simulations make connection to real world, representations that are not in the real world and analogies to help students make meaning such as the sandwich example.