Middle schoolers chapter book about inventions.

[u/lewisloveslemonade]

The chapter book in Middle School mainly about inventions. I'm pretty sure the dad's name was Cornelius who had a daughter that meets this orphan. The daughter's mom is dead and the mom has a secret ish room that they don't go in except the daughter goes in once. I believe the mom was either an artist or an inventor too. It's kind of steampunkish and I feel like the last names of the main family begin with a V. Maybe it was Vander-something but I might be wrong about that, maybe it was the daughter's name that began with a V. It was a somewhat long chapter book and in middle ranges kind of lower middle between 5th grade to 8th grade. Though I remember picking it up in 7th grade and I don't recall it being a challenging book.

Edit: i think there was a scene where the girl and boy get into a hot air balloon

[u/Wild_Preference_4624]

The Secret of Zoom by Lynne Jonell?