Candle and Oxygen Lab

Conducting a science lab with your students shouldn’t be hard. It shouldn’t be a costly or timely endeavor. With that being said, this Candle and Oxygen Lab is neither of these things. The materials list is easy, virtually free, and creates a science experiment perfect for identifying variables. This lab can be used on its own or can be paired with any unit study on air, the atmosphere, or combustion. Read on to see how easy it is!

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Materials Needed

To conduct this lab, you will need 4 different sized jars with lids, 4 tealight candles, and a lighter (preferably a long hand-held one). The hardest thing about this lab set-up is finding four different sized jars. Since I lead science classes from time to time, I keep glass jars from pickles, spaghetti sauce, and jams in my science cupboard. For those of you wanting to extend this lab from a demonstration to an experience, I encourage you to print out our FREE Science Lab Sheets.

Posing Question & Hypothesis

As a teacher, you will want to talk to your students about the variables in the lab. The posing question is, “Will a candle stay lit longer in a bigger jar?” Encourage your kids to write or draw a hypothesis about what they think the outcome will be. Prior to conducting the lab, talk to your students about a fire’s need for oxygen. Without oxygen, a flame will not burn. Since oxygen is one of the main gases in our air, the candle will only burn as long as oxygen is present or the wick burns out. Knowing this information, students can adjust their hypothesis.

Identifying Variables

It is important to help students identify variables. Some experiments make identifying variables difficult. This one makes it easy.

– Responding Variable: the amount of time the candle is lit

– Manipulated Variable: the air capacity in a jar

– Controlled Variable: same candle

Candle and Oxygen Lab Procedures

Start by lighting the candles making sure to leave the lids off until all of the candles are lit. Next, give one lid to each student and have them put the lids on each of the candles at the same time. Now, wait and watch. If you want to gather further scientific data, you can time how long each candle stays lit in each jar, but that is optional.

One by one the candles burn out...

I realize that this lab seems too simple and yet every time I have ever demoed this with a class, they are mesmerized by the flames and love watching them burning out one at a time. My class had been studying about the atmosphere, so for us, this lab was a great way to reiterate that oxygen and nitrogen are the two main gases in our air. At the end of our lab, talk with your kids about any observations made and conclusions drawn. Sweet and simple.

Conclusion

Try our other Science STEM, labs, & experiments! We are all about doing science in the most inexpensive way using what we have handy. Don’t forget to download your FREE Science Lab sheets here!