A bottle of juice is sealed under partial vacuum, with a lid on which a red dot or "button" is painted. Around the button the following phrase is printed: "Button pops up when seal is broken." Explain why the button remains pushed in when the seal is intact.

Presure...maybe

I figured this one out. No need for further explanation. Thanks!

You're welcome! I'm glad you were able to figure it out. But just for clarification, the reason the button remains pushed in when the seal is intact is indeed related to pressure. Inside the bottle, there is a lower pressure compared to the surrounding atmospheric pressure. The button on the lid is designed to pop up when the seal is broken and the inside pressure becomes equal to the atmospheric pressure. As long as the seal is intact, the lower pressure inside the bottle keeps the button pushed in.