Welcome to the first lesson of the Connected Chemistry Ideal Gas Laws unit!

In this unit, we will investigate what causes gas pressure, how it is measured, and how it is affected by the properties of the particles that make the gas and the characteristics of the container they are in. To achieve this goal, we will study gases 

• at the macroscopic level by exploring real world objects such as basketballs, air duster cans, and basketballs.
• at the microscopic level by using computational models.

We will begin our exploration with an air duster can. This everyday object will help us understand:

• How do gases behave in a fixed volume container?
• What are computational models?
  • How do we create them?
  • Why do we need them?
  • How are they related to scientific models?

Let's watch the following video of someone cleverly "hacking" an air duster. This demonstration may give us a better idea on how it works.

Please set your computer aside briefly (do not close this page) and join the classroom discussion that your teacher is going to moderate.

Note: If you the discussion has not started yet, please answer the extra credit question below as you are waiting.

In this unit, we are going to work with a few fundamental assumptions about gases. The first of them is: gases are made up of many individual particles (molecules).

However, we cannot see the gas molecules inside the air duster can; they are too small to see with only our eyes 👀. Instead, we will use  NetLogo 🔗 to develop a computational model to visualize the molecules inside the air duster can as the air is being pumped into it. NetLogo is a free programmable environment for building and running computational scientific models that simulate natural and social phenomena.

Scientific models 🔗 are used to explain and predict the behavior of real objects or systems and are used in a variety of scientific disciplines. They can be expressed in many different ways. For example, your written explanations and sketches can be considered as informal models of the gas behavior in the air duster can.

Below is a simple particle sandbox modeling toolkit. We can use this simple modeling toolkit to construct static systems that include basic particles and barriers. The short video above demonstrates how to use this tool.

Now let's re-create an approximation of our sketched models of the air duster can using the simple modeling toolkit below! 

Please do not spend more than 6 minutes on this task.

Again, please set your computer aside briefly (do not close this page) and join the classroom discussion that your teacher is going to moderate.

Note: If you the discussion has not started yet, please answer the extra credit question below as you are waiting.

The particle sandbox model allowed us to create simple gas molecules and place them inside containers. However, it did not allow us to see how the particles behaved. We can use computer models to animate the particles, too.

Below is another simple modeling toolkit that allows us to define the behavior of gas particles. For simplicity, this toolkit allows you to work only up to 4 particles. The short video on the right demonstrates how to use the blocks below the model to program the behavior of the particles. Please watch it carefully if you are having difficulty with the blocks.

A few quick points:

• Click  to reset the model and click  to run your model.
• Your code should always start with the  block, or the model will not know what to do.
• Your code will be performed by the particles continuously.
  • For example, if you wrote that "each particle + moves zig-zag", each particle in the model will move one step forward doing a zig-zag movement and then move one more step forward the same way, and so on. This will keep going on as long as the GO button is pressed.

Now let's try to figure out how gas behave inside a container!

Please do not spend more than 6 minutes on this task.

Now we can put our static particle sandbox model and our particle behavior block codes together. Let's use the combined modeling toolkit below to:

1. Load your static model design from Page 4* using the  button.
2. Re-create your blocks code and run it within your sandbox model.
3. If the model does not behave as you anticipated, change your experiment design (e.g., add more particles, walls) or blocks-code to manipulate your model.

Note: If you don't remember the code you wrote in the previous step, you should be able to see a link to your blocks code screenshot below the modeling toolkit.

* If you did not save your design, try to recreate it as best as you can. But this time, don't forget to save it.

One last time, please set your computer aside briefly (do not close this page) and join the classroom discussion that your teacher is going to moderate.

Note: If you the discussion has not started yet, please answer the extra credit question below as you are waiting.

In this final section, we will compare all three of our models (written, sketch, and computational).