Candy Snap Materials Science

A supersweet science activity from Science Buddies

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How can you make candy snap? Learn about materials and their physical properties the sweet way by trying your hand at this fun science activity! 

Key conceptsPhysicsMaterials science

Introduction

Background

But what happens if you bend or stretch a material much? Some materials will continue to deform but permanently hold their bent shape instead of springing back. For example, think about what happens when you bend a paper clip. This is called . Materials that can undergo lots of plastic deformation before they finally break are called . Other materials will break very suddenly when you bend them too much—for example, a wooden ruler or pencil. Materials that snap suddenly without undergoing much plastic deformation are called .

But the behaviors of materials are not always the same; conditions such as temperature can have a great effect on how they respond. Engineers who build outdoor structures (such as bridges) or things used outside (such as cars) have to worry about how temperature changes will affect a material's behavior. You wouldn't want a structure that's nice and sturdy on a warm day to suddenly collapse if it gets hot or freezing cold! In this project you'll investigate how temperature affects what happens to different candy bars when you try to bend them in half.

Materials

• Two each of assorted full-size candy bars of your choice
• Two each of assorted "soft" candies such as Twizzlers, AirHeads or Gummi Worms (AirHeads are highly recommended because they are the best at showing the experiment's effect.)
• Access to a freezer
• Pen or pencil and paper (optional)

Preparation

• Place one of each type of your candy items in the freezer about one hour before you start your experiment.
• Leave the other half of your items out at room temperature.

Procedure

• Take one of your room-temperature candy items and hold it on both ends (using both hands).
• Slowly start to bend the full-size candy in half. Pay close attention to how hard it is to bend it.
• Continue bending the candy until it breaks. Pay close attention to how it breaks.
• Note: Some items, such as Twizzlers and Gummi worms, are very flexible, so you might not be able to break them at all by bending them.
• If you would like to make a note of each type of candy and its material behavior during bending and breaking, record each observation after you preform the breaking test.
• Now, take the matching candy out of the freezer and repeat the steps above. Remember to carefully observe how the candy breaks.
• Repeat the procedure for each type of your other candy items. Remember to pay close attention to how hard the materials are to bend and how they break.

Observations and results

Cleanup

More to exploreBrittle versus Ductile Deformation, from FormationStationStretch It! How Does Temperature Affect a Rubber Band?, from Science Activities for All Ages!, from Science Buddies

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