Preview - Ideal Gas Laws - Connected Chemistry 2019

Our experimental setup: the CODAP data analysis workbench

In the previous lesson, we ran 3 experiments and then tried to plot the data by hand. Even with just three experiments, we  started noticing trends. However, we also noticed two important issues:

  1. Reliability issue: The particles' random behavior may lead to fluctuations in our final pressure value.

  2. Practicality issue: We might not be able to precisely plot the data by our hands.

 

Scientists try to overcome such issues by using an approach called "statistical mechanics 🔗". To put it simply, they collect lots of data and then use statistical methods to determine mathematical relationships between variables.

Below, you will see a CODAP workbench. CODAP is a web-based data analysis platform that will make it much easier for us to run many experiments at once. It will also make it much easier to plot our data and find out mathematical relationships between the variables.

 

Let's begin with familiarizing ourselves with the CODAP environment:

  1. Run three experiments for 15 ticks: with 100 particles, with 200 particles, and with 300 particles. (p.s.: you can speed up the model to get the results more quickly)
  2. Observe how the results of each experiment is automatically transferred to the "Experiment results" table on the right.
  3. Drag the num_particles variable to the x-axis of the plot plot as shown in the GIF on the right.
  4. Drag the last_pressure_value variable to the y-axis of the plot plot as shown in the GIF on the right.
  5. Observe the resulting plot. Then answer the questions below the CODAP workbench.

 

Referenced Questions

These questions were answered in the previous steps. They are provided here for your reference.

Record your measurements in the table below.

It may be too hard to notice trends in data by just looking at raw numbers. Mark your data points on the following sketch in order to see if there is any correlation 🔗 between our two variables (x = number of particles, y = pressure). Do not worry about perfect precision when you mark the points.

Questions

Please answer the questions below.

How do your hand-collected data points and your hand-drawn plot compare to the ones you created with CODAP? (write min. 1 similarity and 1 difference). 

How confident are you with your findings? Do you think the relationship you found may change if we conduct more experiments? Do you think it will stay the same? Explain how & why? (min 2 sentences)

In the next page, you are going to conduct your first computational experiment. To keep things simple in this lesson, you will design an experiment for a pre-determined research question:

Dependent variable: (P)ressure
Independent variable: (N) umber of particles
Research question:

Is there any mathematical relationship between these two variables?

If yes, what is the nature of this relationship?

 

When designing your first computational experiment using the table above, you should have the following considerations in mind: 

  1. Collect sufficient number of data points to find a reliable answer to the research question.
  2. Test different values for the independent variable (N) to find a reliable answer to the research question (min. 5 different values).
    1. Enter each value for independent variable in a new row.
    2. Add more rows by clicking any of the the   buttons.
  3. Design an experiment that can be practically conducted within CODAP.

Note: You will run this experiment within the CODAP workbench in the next page.

Notes

These notes will appear on every page in this lesson so feel free to put anything here you'd like to keep track of.