--Book title help

I seem to reme ber a book from like 20 years ago (25?) any how the subject
was a kid or 2 was exploring a museum or park where they was showin how the
people lived on amish farms a hundred or so years ago (like a school room
for example with plexiglass so you can see but not touch) well magic was
involved in that when the kid crushed a special flower agenst the glass he
"fell through" to the past.... the rest is how he adjusts to the past &
tryes to figure out how to get back to the present.....

It keeps coming to my mind every now & then....

if someone can supply a title/author .. I would be Greatful

Sam