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If you have ever heard the sounds of chip packets slamming, you’ve probably wondered why they are so loud. It’s actually due to a temperature change known as the glass transition temperature. It also makes the chips appear to be crunchier. Regardless of how you look at it, the sound of chip packets makes you cringe. The next time you’re at the grocery store, try to open a packet in a quiet room.
It’s the glass transition temperature
The glass transition temperature, or Tg, is an important property of polymers. It signifies the point where the polymer’s structure changes and becomes sticky. The Tg of most synthetic polymers is between 170,000 and 500,000 degrees Fahrenheit.
To understand how the Tg of food wrappers affects the noise they make, it’s important to understand how glassy materials change over time. At room temperature, high moisture bread is in a rubbery state. By freezing it, the bread undergoes a glass transition. In science, this is measured using differentiators and dynamic mechanical thermal analysis. During this process, the stress applied to the polymer changes according to the temperature and frequency around T g.
Fortunately, there are solutions for this problem. For example, polylactic acid, the main ingredient in most food wrappers, has a glass transition temperature of just over room temperature. Because of this, it is possible to handle food wrappers in such a way that results in a loud and disturbing crinkling sound. Frito-Lay redesigned their bag after receiving complaints from consumers.
It causes crinkling
The noise that can be caused by food wrappers is common and often annoying. The noises can be produced when the wrapper is crushed or opened. You might also hear these noises when removing wrapped candy. These are especially annoying in theaters, where the noise from the wrappers is often a source of irritation. Plastic and paper items can also cause noises of this kind.
It makes chip packets sound like they’re crunchier
Chip packets make a sound when you open them, and some researchers believe it is the same for any food. The louder the sound, the fresher a chip is perceived to be. This was found in a study conducted by Oxford University’s Charles Spence. People in the study ate the same type of chips from the same package, and the louder the sound, the fresher they rated it.
This sound is a bone-conducted auditory cue that is transmitted through the jaw. It plays a significant role in judging food, and future research should test whether bone-conducted auditory cues can be manipulated or cancelled when eating.
People associate loudness with freshness, and loud chip packets make them sound crunchier. Manufacturers do this purposely. They want people to associate the sound of crunch with the freshness of their food. To test this, they conducted a study where 20 participants rated 180 Pringles crisp packets. In the study, the participants listened to the sound of the crunch with headphones and assessed their crisps based on how loud it was.
When people eat chips in public, they make a lot of noise. The sound of opening a packet or chip bag has become part of pop-culture. While this is perfectly acceptable in your own home, it’s not appropriate in public places.