Using PASCO Sensors to Teach Reaction Kinetics in Real Time

One of the challenges of teaching chemical kinetics is that reactions often happen too quickly (or too slowly) for students to clearly observe the changes. Traditionally, we rely on graphs drawn after the event — plotting concentration vs time or rate vs concentration — but by then, the “moment of reaction” has long passed.

This is where PASCO sensors transform the classroom. They let us see the reaction unfold in real time.

The Setup

Using PASCO’s wireless sensors, students can track measurable changes as a reaction progresses:

• Colourimetry → Monitor absorbance to follow the disappearance of a coloured reactant.

• Conductivity → Measure changing ion concentrations during neutralisations or decomposition.

• Gas Pressure → Follow reactions that generate gases, such as the decomposition of hydrogen peroxide.

• Temperature → Observe exothermic or endothermic changes dynamically.

The data streams directly to a computer or tablet, where graphs plot in real time.

Why It Works for Teaching

1. Instant Feedback – Students don’t just see bubbles or colour changes; they see data points building into a live curve.

2. Connection to Theory – The shapes of those curves (straight lines, exponentials, plateaus) connect directly to rate laws and order of reaction.

3. Engagement – Watching a graph draw itself feels like an experiment and a discovery, not just a worksheet.

4. Accuracy – Sensors eliminate the stopwatch error of “start–stop” timing by hand.

A Classroom Example

Take the classic iodine clock reaction. With a colour sensor, students can follow the disappearance of iodine rather than waiting for the sudden “blue-black” end point. The rate law becomes something they see forming on the screen.

Or consider hydrogen peroxide decomposition. A gas pressure sensor allows the class to track oxygen evolution second by second, turning fizzing bubbles into hard data.

The Bigger Picture

PASCO sensors bridge the gap between theory and practice. Instead of drawing idealised curves on the board, we can show the messier, noisier real curves that happen in the lab. And in doing so, students learn that science isn’t just equations — it’s measurement, data, and interpretation.

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🔬 In the end, teaching kinetics with real-time sensors helps students see chemistry not as abstract maths, but as something dynamic and alive — reactions unfolding before their eyes, and graphs writing themselves into understanding.