How do you keep apples from turning brown? Do all apples turn brown at the same rate? Let’s try to answer these burning apple science questions with an apple oxidation experiment that is pretty quick and easy to set up at home or in the classroom. Pair it with other fun apple science experiments!


Try This Apple Browning Experiment For Fall

Have you ever found a bad spot on an apple or opened a container in a lunch box filled with apple slices that were once pearly white and now look a bit on the used-up side. The bad spot is definitely not tasty, but the slightly browned apples aren’t all that bad!

Is it safe to eat brown apples? My son tasted the brown slices of his favorite apple, the honey crisp, and declared them still ok. Not all apples are similar in their rate of browning!

How do you keep apples from turning brown? Lemon juice is often suggested as a solution for keeping apples from turning brown. Does lemon juice really work and how does it stop or slow the browning process?

Let’s try a simple apple experiment and find out how to stop apples from browning!

Using The Scientific Method With Kids

The scientific method is a process or method of research. A problem is identified, information about the problem is gathered, a hypothesis or question is formulated from the information, and the hypothesis is tested with an experiment to prove or disprove its validity.

Sounds heavy! What in the world does that mean?!? It means you don’t need to try and solve the world’s biggest science questions! The scientific method is all about studying and learning things right around you.

As children develop practices that involve creating, gathering data evaluating, analyzing, and communicating, they can apply these critical thinking skills to any situation.

READ MORE: The Scientific Method For Kids With Examples

Note: The use of the best Science and Engineering Practices is also relevant to the topic of using the scientific method. Read more and see if it fits your science planning needs.

Helpful Science Resources To Get Your Started

Here are a few resources that will help you introduce science more effectively to your kiddos or students and feel confident yourself when presenting materials. You’ll find helpful free printables throughout.

Set Up An Apple Browning Science Project

Science projects are an excellent tool for older kiddos to show what they know about science! Plus, they can be used in all sorts of environments including classrooms, homeschool, and groups.

Kids can take everything they have learned about using the scientific method, stating a hypothesis, choosing variables, making observations and analyzing and presenting data.

Want to turn this apple oxidation experiments into an awesome science fair project? Check out these helpful resources.

Apple Science Experiment with Lemon JuicePin

Why Do Apples Turn Brown?

There’s great science behind the process of why an apple turns brown or why rotten spots are brown.

The simple science is that when an apple is damaged, or even cut into slices, the enzymes in the apple react with the oxygen in the air, which is a process called oxidation. The apple produces melanin to protect the apple which is the browning you see.

We watched this short video on Why do Apples Turn Brown? which digs deeper into the exact science of polyphenol oxidase (PPO) enzymes. It’s a mouthful!

How Does Lemon Juice Stop Apples From Browning?

Lemon juice helps keep the apple from turning brown because it is full of ascorbic acid (Vitamin C) and it has a low (acidic) pH level. Learn more about the pH scale.

Ascorbic acid works because oxygen will react with it before it reacts with the polyphenol oxidase enzyme in the fruit. What else might prevent apples browning in a similar way?

Why Do Apples Turn Brown?

Alternatives To Lemon Juice

We investigated whether lemon juice on apples stops them from turning brown in the experiment below. Why not extend the learning and compare different ways to prevent cut apples from browning!

You could also test…

  • Ginger Ale
  • Salt Water
  • Ascorbic Acid Powder
  • Plain Water

Get your printable apple experiment worksheet!

Apple Oxidation Experiment

This is a great experiment to set up using the scientific method for kids. Use our printable apple browning experiment worksheet below to record your observations.

The independent variable will be the type of apple, and the dependent variable will the amount of lemon juice you add to each apple. Can you think of any other dependent variables?


  • Apples! (We used 5 varieties of apples since we had just completed our apple 5 senses science activity beforehand.)
  • Lemon Juice (or real lemon)
  • Paper Plates, Knife, Small Cups (optiona)
  • Printable Journal Pages

Set Up:

STEP 1: Label the paper plates with the name of each type of apple you are using.

STEP 2: Then cut two wedges of the same size out of each apple.

STEP 3: Place one wedge in a small dish and the other on the plate alongside the rest of the whole apple.

STEP 4: Squeeze a little lemon juice over each slice in the dishes and mix to coat evenly. Dump out excess juice. Do this for each apple.

Apple Science Lemon Juice Experiment for Kids Fall STEMPin

STEP 5: Now wait and be patient. Record your observations.

If you want, set out a timer to get an accurate measurement of the time it takes for each apple to turn brown. This way you can record results in number of minutes for drawing conclusions later.

Our Results

  • Which apple turned first?
  • Did they all turn equal shades of brown?
  • Does the apple slice coated in lemon juice taste different than the plain apple slice?
  • Does the brown apple slice really taste all that bad?
  • Did the lemon juice really work?


He went on to happily eat both slices of cut apple and found them tasty. Fall is a great time of year for exploring apples!

Apple science lemon juice experiment why do apples turn brown?Pin

More Fun Apple Science Activities

Printable Preschool Apple Activities Pack

Get ready to explore this year with our growing Preschool STEM Bundle!

What’s Included:

There are 5 fun preschool themes to get you started. This is an ” I can explore” series!

  • My 5 Senses
  • All About Me
  • Science and Scientist
  • Apples

Each unit contains approximately 15 activities, with instructions and templates as needed. Hands-on activities are provided to keep it fun and exciting. This includes sensory bins, experiments, games, and more! Easy supplies keep it low cost, and book suggestions add the learning time. 

Or grab the Apple Preschool Pack on it’s own!



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