In Petri Dish, players are immersed in a virtual world complete with its own rules and internal logic. Players learn about the world by interacting with it. It is a lot like being dropped into a foreign city and learning about the city by walking around and trying to do things.

Learning by immersion is a natural process. For our own survival, we are hard-wired to analyze what is happening around us and to try and make sense of those observations. However, for immersive learning to be most effective, the environment must be carefully designed to facilitate sense-making. We do that in Petri Dish by making:

1. the world as transparent as possible,
2. the set of rules governing the world as small and as intuitive as possible, and
3. the actions that the player can take within the world as limited as possible.

Concepts Players Will Learn by Immersion

By simply playing the game, casual players will note that:

• the cell membrane regulates what enters and exits the cell;
• cells build proteins to do things;
• proteins are encoded in the cell’s genome;
• proteins transport molecules and catalyze chemical reactions to build new molecules;
• proteins need energy to operate, which is why cells need energy to survive;
• cells must be able to build all of the molecules they need from the molecules they take in from the environment;
• cells obtain energy by breaking glucose down into CO2;
• proteins are built from amino acids, genes from nucleotides, and membranes from phospholipids;
• reproduction uses up a lot of a cell’s resources; and
• genes are copied during reproduction and each daughter cell receives a complete set from the parent cell.

That is already much more cell biology than many students typically learn in middle school, or even high school. And players will understand this on an intuitive level where it seems obvious and just makes sense to them. Players who then become serious about exploring Petri Dish will also note that:

• glucose from the environment is the source for all carbon atoms in a cell, PO32- for all phosphorous atoms, and NH4+ for all nitrogen atoms, which means that the total number of each type of atom is conserved and atoms are cycled through the system;
• the rate of a chemical reaction depends on the concentration of the reactants;
• the rate of a metabolic pathway is limited by the rate of its slowest reaction;
• localizing a chemical reaction or a pathway in an organelle can speed up the reaction or pathway, but organelles are expensive to build;
• cells must regulate individual pathways and decide which proteins to build;
• the control systems in a cell are decentralized and operate through feedback mechanisms and chemical sensors;
• designing a cell involves a lot of trade-offs;
• no single cell can be well-adapted to every environment;
• easy-to-understand local mechanisms within a cell can result in complex emergent behaviors from the cell; and
• the survival of a species/population depends more on population dynamics than on the ability of a single cell from the species/population to survive.

Some of these concepts are considered too advanced for middle or high school students, but we are confident that they can learn them through immersion if we can engage them in Petri Dish.