Elon Musk's Rice Krispie treats

Elon Musk confused his 22.4 million Twitter followers on Wednesday by posting a mysterious photo of some snacks next to a toy car. The post, which came with no text, shows three Rice Krispie Treats with stickers of the cereal mascots Snap, Crackle, and Pop, alongside a miniature Tesla Model S and a model version of Mars on a stand.

Musk posted the photo five hours after a fact shared by author Matt Porter, suggesting a link between the two. Much like how the Tesla and SpaceX companies referenced with the two models use physics to change the world, so too do the three mascots. First, a quick primer: physicists can measure the displacement of an object by understanding its first position and its last. Dividing the change by the time it took to change gives us its velocity, or speed, which is known as the first derivative of displacement. Measuring how fast the speed is changing gives us the object’s acceleration, the second derivative of displacement. The third derivative of displacement, following this same pattern, is known as jerk.

Snap, Crackle and Pop.
Snap, Crackle and Pop.

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What does this have to do with cereal? The fourth, fifth, and sixth derivatives of displacement are known as snap, crackle and pop. That’s according to a 2008 research paper by Maciej Dunajski and Gary Gibbons listed in Cornell University Library’s general relativity and quantum cosmology section. A 1996 web page on the University of California, Riverside website also notes the name of the three derivatives, although it refers to them as “less serious suggestions.”

Unfortunately, it seems unlikely the Kellogg Company intended their mascots to represent an obscure physics joke. A 1929 advertisement, published the year after Rice Krispies first hit shelves, first advised people to listen “as they merrily snap, crackle, and pop in a bowl of milk. If you’ve never heard food talking, now is your chance!” Artist Vernon Grant created the mascots in 1933. The Dunajski and Gibbons paper credits these early ads for later introducing the physics term.

Musk will have to content with these three a lot over the next few years. Tesla is gearing up to launch a cheaper sports utility vehicle, a pickup truck, a semi, and a sports car. SpaceX, meanwhile, is planning to send humans to Mars in 2024.

A lot of vehicles over the next few years will need to snap, crackle and pop.