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Candy Core Samples

3 reviews


Active Time
10-20 minutes
Total Project Time
10-20 minutes
Key Concepts
Geology, core samples
Ben Finio, PhD, Science Buddies
Candy Core Samples


Act like a geologist in this fun activity as you drill "core samples" from candy bars using a straw. Can you identify the type of candy bar just from a sample? Try this activity to find out!

This activity is not recommended for use as a science fair project. Good science fair projects have a stronger focus on controlling variables, taking accurate measurements, and analyzing data. To find a science fair project that is just right for you, browse our library of over 1,200 Science Fair Project Ideas or use the Topic Selection Wizard to get a personalized project recommendation.


  • Assorted mini or fun size candy bars like Snickers®, 3 Musketeers®, and Milk Way®. Avoid solid or "hard" chocolate bars like Hershey® bars.
  • Clear drinking straws (biodegradable/compostable straws are more environmentally friendly than plastic straws!)
  • Scissors
  • Small plate
  • Paper towels
    Materials for candy core sample activity

Prep Work

This activity works best with candy bars that are at or slightly above room temperature. If the candy bars are too cold, it will be hard to poke a straw through them, and they will crunch or break. If they are too warm, they will be squishy and gooey, making it difficult to get a nice sample. If necessary, briefly put your candy bars somewhere to raise or lower their temperature. For example, you can put them in the refrigerator for a few minutes to chill them or leave them on a sunny windowsill to warm them.


  1. Unwrap a candy bar and put it on a plate.
  2. Carefully poke a straw through the top of the candy bar.
  3. Make sure you poke the straw all the way through the bottom of the candy bar. You may need to gently twist or wiggle the straw to get it all the way through.
  4. Gently pull the straw back out of the candy bar.
  5. Use a damp paper towel to wipe off the outside of the straw.
    Think about:
    Are individual layers visible in your candy "core sample"?

    A cylindrical core sample that has been removed from a candy bar, inside a clear straw.
  6. Use scissors to cut the straw just above the candy inside.
  7. Place your core sample next to the wrapper for the candy bar, so you can keep track of which candy bar it came from.

    The candy core sample in a straw next to a Snickers® wrapper.
  8. Repeat steps 1–7 for at least one other type of candy bar.
  9. Place your core samples side by side. (Be careful not to lose track of which one is which!)
    Think about:
    How are your core samples different from one another? Do any of them have similar layers?

    Four candy core samples placed next to each other. They have different visible layers of chocolate, caramel, and other ingredients.
  10. Have a friend take a core sample without showing you which candy bar they use and then give you the sample.
    Think about:
    Can you identify which type of candy bar the sample came from by comparing it to the other samples?


You can "dispose" of any remaining candy bars and core samples by eating them—just do not eat too much candy all at once!

What Happened?

Many candy bars have multiple layers of different ingredients like caramel and chocolate. When you take a cylindrical "core sample" using a clear plastic straw, these layers are clearly visible inside the straw. You can do a side-by-side comparison of the layers in different candy bars. You can also match an unknown sample to an existing sample to identify the source of the unknown sample. Read the Digging Deeper section to learn more about how geologists use real core samples to explore Earth and other planets.

Digging Deeper

Geologists use large drills to take core samples of soil and rocks on Earth. They examine the core samples for different layers, which can tell us things about Earth's history, like the climate or the types of animals that were alive at a certain time. Scientists can even figure out when volcanoes erupted in the past by looking for layers of volcanic ash!

We can also use core samples to learn about other planets and bodies in our solar system. Previous NASA missions gathered core samples from the Moon, and the Mars 2020 Perseverance rover will gather core samples from rocks and soil on Mars for future analysis.

icon scientific method

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For Further Exploration

  • This activity can be done with layers of Play-Doh® instead of candy.
  • If you have difficulty taking cylindrical samples with drinking straws, you can cut the candy bars in half with a knife to view their cross-sections and see and compare the layers.


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