Summary

In this demo, students will observe the combustion of methane using hands-on practices.

Grade Level

High school

Objectives

By the end of this demo, students should be able to

• determine the chemical equation for the combustion of methane gas.
• write a balanced chemical equation for the reaction between methane and oxygen.

Chemistry Topics

This lesson supports students’ understanding of

• Chemical changes
• Stoichiometry

Time

Teacher Preparation: 10 minutes

Lesson: 10 minutes

Materials

• Dishwashing liquid, ~100 mL (Store brought bubble solution also works well)
• Glycerin, ~15 mL
• Water, distilled or deionized, ~900 mL
• Trough or large Pyrex glass bowl, ~1 L
• Filter funnel, ~75 mm
• Tubing, rubber, ~10–20 ft
• Methane gas source
• Meter stick
• Matches
• Masking Tape
• Candle, ~5 inches 

Safety

• Wear safety goggles and chemical-resistant gloves at all times during demo.
• Only light bubbles when they are well above students’ heads and away from their faces.
• Do not light bubbles near any heat or smoke detectors.
• Shut off the gas source immediately after the bubble forms.

Teacher Notes

Procedure

1. Mix ~100 mL of dishwashing detergent, ~15 mL of glycerin, and ~900 mL of water directly in the trough or large Pyrex glass bowl. (Note: you can also purchase premade bubble solution).
2. Connect the funnel to the gas source with the rubber tubing.
3. Tape the candle to the meter stick and then light the candle.
4. Turn on the gas valve on and adjust the flow to prevent the foaming from occurring when the funnel is dipped into the bubble solution.
5. Dip the funnel into the bubble solution and hold the funnel upwards to allow a bubble to form. (Note: You may have to turn the funnel to one side of shake it in order for the bubble to dislodge–I found this part to be tricky because the bubble would burst before it even had a chance to dislodge. A tip to prevent the bubbles from bursting is to coat the edges and the inner walls of the funnel with glycerin using a Q-tip before dipping it into the bubble solution).
6. When the bubble is away from your face and above your head, place the candle flame next to the bubble (making sure that the flame touches the bubble).
7. Have students observe the flame.
8. Alternative title for the demo is the Dragon Ball Z demo.

Note: Question number 5 in the analysis can be a bonus demo for students. Make sure to wet your hand thoroughly with water before placing the methane bubble solution on it. Grab a handful of bubble solution and ask a student to light a match and touch the match to the bubble solution on your hand. Students will observe the flame formed. Try not to move hand around when the flame is formed.