Easy Science Fair Idea for Elementary School

ApplesMy son’s school has a voluntary Science Fair this week.  My son has been in love with the Science Fair since Kindergarten.  He thinks its cool and he loves that the kids all get a participation ribbon.  Last year, my son took Second Place at the fair with his experiment on “Which Liquid Would Rust the Nail the Quickest?”  That pretty much sealed the deal on him forever participating in the Science Fair.  Because my son’s experiment required the use of some chemicals, it wasn’t one that he could do entirely on his own.  I wouldn’t recommend it for us Slacker Moms… it meant that I always had to be there to observe and make sure he didn’t splash bleach in his eye.

If your child has to do a Science Fair project and you don’t want to have to do it for them help, then I recommend totally stealing recycling this idea.  Even if your kid is in the 4th grade.  Experimental science is a lot of fun for kids and this one keeps it fun for the parents too.

Preserving Apples

What you need:

  • Apples.  You could use pear or avocado, but apples are cheap.
  • Lemon juice, salt, sugar, and whatever else your kid thinks might be a good preserving agent.  Try butter or oil.  It doesn’t all have to make sense.
  • Paper and pencil to record results.
  • Camera to document daily with photos (or be an especially mean mom and make them draw the observations themselves.

For your kid to get credit, they must follow the Scientific Method.


Purpose: Which agent will prevent an apple from turning brown?

Hypothesis: What do I think will happen? Identify which you think will prevent browning and which you think won’t work.

Procedure: List out your materials and the steps (ie. 1. cut apples in half, 2. cover cut apple with preserving agent, 3. Document what happened)

Result: Mark which prevented browning the best. Don’t forget about your “control” apple – the apple that you don’t apply anything to.  This is what all the preserving agents can be compared against. You’ll need to observe this over the course of a couple of days.  You’ll probably want to either take photos or force encourage your child to draw pictures.

Conclusion: Enzymes in fruits cause oxidative browning when fruits are peeled or cut. The enzyme is called polyphenol oxidase or tyrosinase.  It reacts with oxygen and iron-containing phenols that are also found in the apple. The oxidation reaction basically forms a sort of rust on the surface of the fruit. You see the browning when the fruit is cut or bruised because these actions damage the cells in the fruit, allowing oxygen in the air to react with the enzyme and other chemicals.

The whole thing should just a few hours over the course of a few days, including the time it takes to make your fancy poster-board. And you can relish in the fact that you really had nothing to do with the project.  Your child learned something.  And you didn’t have to grow any weird plants using milk or soda as their “water.”

This post is dedicated to the wonderful Susan Nieber who inspired many of us as WhyMommy.  We love and miss you, Susan. 

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