Step 1: What You Will Need
1. A glass jar
2. A source of flame (lighter or matches)
3. A candle
4. And a balloon of carbon dioxide (not pictured). If you don't have any on hand, learn how to make it.
Step 2: Step One: Release the Gas
Take the glass jar and carefully and slowly release a slow stream of the CO2 gas into the jar. Take your time.
Step 3: Step Two: Light the Candle
Step 4: Step Three: Extinguish the Flame
Without tipping the jar, slowly move it over next to the candle. Then carefully make a pouring motion with it right over the candle. If you did it right, the candle should go out almost immediately. If it didn't work, try "pouring" it a couple more times. If it still isn't working, go back and retry with a new jar of gas. It often takes more than one try- it took me three to make this video.
After that, you're done! Remember to clean up your mess.