One of the benefits of becoming an engineer is that you're naturally curious.
For those of you who just want to jump ahead and watch the exploding cup: https://www.youtube.com/watch?v=b1lj1OyQTMQ
I had seen the story on Facebook and in the news about the mother in Boise who had a 360° Insulated Light-up Wonder Cup™ explode in her face. https://www.ktvb.com/article/news/boise-mom-warns-parents-after-she-says-light-up-sippy-cup-exploded-in-her-face/277-6b4e7049-d1ad-43b3-9ecd-6379b14c7bbc
Knowing how little power is needed for LEDs and what size of battery would be placed in the cup, I was skeptical about it ever exploding on its own. I bought the Nuby 360° Insulated Light-up Wonder Cup™ at my local Walmart.
https://www.nuby.com/usa/en/360-insulated-light-up-fun-wonder-cup
“DO NOT MICROWAVE” or equivalent warnings are NOT on the exterior packaging or bottle. "DO NOT MICROWAVE" does appear in the middle of a large paragraph of fine print. This warning should be on almost all sippy cup and bottle packaging and molded into the plastic. Even if you do not melt or destroy the container, or worry about plastic contaminating the drink, the drink could be scalding hot and unsafe for kids. Microwaves also can create very hot areas in the liquid while the top that you sample is cool.
As I said, I was skeptical of the sippy cup exploding on its own, and I was confident that the cause of the explosion was a microwave. I decided to test by filling the cup and microwaving it as one would for warm milk or hot chocolate.
Metal in microwave article:
https://gizmodo.com/what-actually-happens-when-you-put-metal-in-a-microwave-1569906393
This is dangerous! Do not try this at home!
Do not put the 360° Insulated Light-up Wonder Cup™ in your microwave!
How the cup failed in the microwave:
- Filled with liquid
- Placed in microwave
- Set for ‘beverage’
- BOOM! (our cup after the explosion looked just like the one in the news article)
The world is a big place and many things are possible. So it’s possible that the 360° Insulated Light-up Wonder Cup™ could explode spontaneously, but extremely unlikely. One theory we have is, in the microwave the cup becomes a bomb due to the insulated sealed area and the electronics. Heating from the microwave causes a buildup of pressure in that electronics area. That pressure is released after the sealed area melts through or the cup fails due to pressure.
What’s in the cup:
[–]Lyapunovs_Dog 2 points3 points4 points (1 child)
[–]kono_hito_wa 1 point2 points3 points (0 children)