Yesterday, as part of my Innovative Teaching Grant from the Pearland ISD Education Foundation, my students completed a data collection lab.

**Objective**

- Model pressure versus volume using inverse variation

**Procedure**

Although students were in groups of three to four, each student collected their own data. Members of the group rotated between three jobs: syringe, calculator, directions.

A syringe containing 15 mL of air was screwed onto the gas pressure sensor, which was connected to the TI-Nspire. The pressure of the air was recorded using the Data Quest App on the TI-Nspire.

The gas was compressed to 14 mL, and the pressure was recorded.

The pressure reading was also recorded for 13 mL, 12 mL, 11 mL, and 10 mL.

**Analysis**

An example of one student’s data collection.

Students noted that as the volume increased the pressure decreased.

The constant of variation was calculated by multiplying pressure and volume. Then the average was calculated.

Using the mean value for the constant of variation, a model was written and graphed on the scatterplot of the data.

**Results**

Students used their models to predict the pressure for a volume of 20 mL and 5 mL. Based on their predictions, they were able to determine that when the volume of a gas is decreased from 40 mL to 10 mL, the pressure will quadruple.