Oct 5, 2016

Candle and Oxygen Experiment

Once a week I like to do something fun with the kids in our homeschool. Currently we are using the book Laura and Grandpa Discovering Science Together. (Thank you Grandpap for this gem!) We have really enjoyed the many hands on experiments within it. I recommend it for those with younger kids because it keeps their interest and makes them feel a part of the story. The materials used are common household items, or in the case of the purple cabbage experiment, cheap to get. (I know I can't be the only one that doesn't keep purple cabbage, right?)

Before starting I do suggest stressing the dangers of matches, and a reminder that this experiment, if done again, will need to be done with adults for obvious reasons.

You will need:
matches (or long handled lighter.......your knuckles will thank you if you have one available)
clear, clean glass bowl or jar
plate or saucer large enough to cover the top of the bowl/jar
baking soda

The first thing we did after lighting a candle was blow gently to see how the flame reacts. I asked why they thought the flame danced and what do they think would have happened if they had blown harder. The next step was putting the candle in a jar and blow from the same position as before. I had them describe what happened and/or didn't happen and to explain why they thought it was different.

The next step was placing a saucer over the top, observation, and discussion about the results. This is where we began learning about how fire needs oxygen to burn and what they thought happened to it inside the jar.

Because I didn't have a dropper and was tired of singing the hair off my fingers I found a glass bowl for this next step. I had one of the kids put baking soda into the bottom of the bowl and to nestle the candle in the middle. After relighting the candle I added a few small spoonfuls of vinegar to the baking soda and we discussed what happened next. We talked about how chemical reactions can also remove oxygen from an area to put out a fire. This was taken a step farther to include how this principle works for fire extinguishers*.

As a bonus when my daughter played with the vinegar and baking soda (after the candle was removed of course) she noticed how clean her hands were. I explained it is my favorite cheap cleanser, especially for cleaning the stove....needless to say she wasn't quite as thrilled with that bit of information as she had been with the experiment. I believe the response was a giggle, eye roll, and "mmmooooooommmm".

This one was our favorite so far, but the runners up would be the cabbage paper (ph and acid) experiment, and the "rubber" egg.

*For my PA homeschool friends this would be good to use for part of the fire safety requirements.

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