{"id":110,"date":"2020-06-11T22:02:34","date_gmt":"2020-06-11T22:02:34","guid":{"rendered":"https:\/\/soundstasty.net\/?p=110"},"modified":"2020-12-17T00:17:06","modified_gmt":"2020-12-17T00:17:06","slug":"acoustics-of-watermelons","status":"publish","type":"post","link":"https:\/\/soundstasty.net\/acoustics-of-watermelons\/","title":{"rendered":"Knocking on Watermelons"},"content":{"rendered":"\n

Today we are going to talk about something very tasty…<\/p>\n\n\n\n

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W A T E R M E L O N S !<\/figcaption><\/figure><\/div>\n\n\n\n

As a kid I remember going to the grocery store with my dad and seeing him knock <\/strong>on various watermelons to determine which one is the most ripe and optimal for eating. I never really understood the method to his madness. I would try to mimic his actions, but with my lack of patience I would just end up picking whichever one looked the most round and \u201ctasty\u201d. <\/p>\n\n\n\n

Can you tell if a watermelon is tasty by knocking on it? <\/h3>\n\n\n\n

I have heard other people mention that there are tricks to determine the ripeness of a melon but I never thought to turn to academia for help. Wildly enough, there are actually quite a few papers about the acoustics of melons and the properties of their ripeness. Don\u2019t believe me? Look at this<\/a>, this<\/a>, and this<\/a>. <\/p>\n\n\n\n

Before diving into some research, I decided to conduct a mini interview with my dad to learn more about how he stumbled upon this. He told me that when he was a refugee in Pakistan he sold lots of watermelons. (He\u2019s got a lot of stories as you can imagine.)<\/em> His strategy was to bring the melon close to his ear and squeeze it to determine if you can hear it crack. According to him, the crack was a sign of the melon being ripe and a good indication that it would be tasty. He basically trained his ear to pick up on what\u2019s tasty or not. Let\u2019s see if science agrees with the street vendor. <\/p>\n\n\n\n

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Random pic of a street market selling watermelons<\/figcaption><\/figure>\n\n\n\n

For today\u2019s post the paper<\/a> I am reviewing was published in the Personal and Ubiquitous Computing Journal and it came from a team at the Future Cities Laboratory in Singapore (fancyy<\/em>). The title of the paper is pretty self explanatory: \u201cClassifying watermelon ripeness by analyzing acoustic signals using mobile devices<\/strong>\u201d. The research team developed an Android app to crowd-source data for identifying watermelon ripeness in real-time while also providing data for their classification model. The main motivation of the study was to help shoppers determine if a watermelon is ripe using the knocking method I have seen my dad use. <\/p>\n\n\n\n

One of the main factors that contribute to ripeness is the sugar content in the watermelons and the authors note that different sugar levels correlate to a different acoustic response. From the start the authors cite quite a few papers that analyze the acoustic impulse response of watermelons, which means my dad\u2019s logic was already valid. Their general characterization of ripeness is that ripe watermelons sound dull while unripe melons have a tighter and more metallic sound. <\/p>\n\n\n\n

What does a tasty watermelon sound like? <\/h3>\n\n\n\n

For those who don\u2019t eat, breathe, and sleep acoustics, the terms \u201cdull\u201d and \u201cmetallic\u201d may not mean much. To better describe what the authors are talking about I decided to consult YouTube for some examples. <\/p>\n\n\n\n

I watched like 10 watermelon videos and I found it interesting how people describe the sounds. It was definitely not consistent which I can see why this may seem like more of an art than a science. Here is a short video with a good recording of watermelons at different stages of ripeness. <\/p>\n\n\n\n

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