Introduction
Three elements must be present at the same time for a flame to burn:
- Fuel
- Oxygen
- Heat
If any of these elements are reduced or removed then a flame will be extinguished. This experiment uses the DrDAQ's Oxygen In Air sensor to monitor the oxygen level required to keep a flame burning.
Warning - as this experiment requires the use of matches adult supervision will be required
Equipment required (See Fig1)
- PC with PicoLog data logging software installed
- DrDAQ
- Oxygen In Air sensor (DD103)
- Temperature Sensor (DD100)
- Bowl of water
- Glass Jar
- Dark Room (for light sensor)
Equipment setup
- Connect the DrDAQ data logger to the parallel port.
- Attach the Oxygen and Temperature sensors to the top of the glass jar. Keep all the sensor leads a safe distance away from the candle.
- Connect the Oxygen In Air sensor DD103 and the Temperature Sensor DD100 to external sockets 1 and 2.
- Configure PicoLog to take a sample every 250 milli seconds for 200 samples.

Fig1. Setup
Carrying out the experiment
- Start PicoLog recording
- Light the candle
- Place the glass jar with the sensors attached over the bowl of water (As seen in Fig1)
- Hold the DrDAQ's onboard light sensor to the glass jar
- Once the candle has been extinguished leave the experiment to settle for a couple of seconds
Questions
Qu.1 What two bi-products were produced by the flame?Qu.2 At what point did the candle extinguish?
Qu.3 How does the graph show you that the candle uses oxygen?
Qu.4 What oxygen level is required to keep the candle burning?
Cart