The ark was soundproof?

Continuing our visual series, here is something I saw in a public park playground recently:

Let me repeat, this was a public park, county operated. The text reads as follows:

(upper right): Once there was a man named Noah who was warned by God of a great flood. Noah began to build an ark that was 450 feet long, 75 feet high and 45 feet wide.
(upper center): The ark was built with cypress (gopher) wood that was coated, both inside and outside, with a tar-like substance to make the ark waterproof and soundproof. The ark had three levels with one door.
(upper left): Seven days before the flood came, Noah began to stock the ark with food and he led the land animals, birds, reptiles and his family two by two into the ark.

(middle right): It rained for 40 days and 40 nights and the whole earth was covered with water. With water from the sky and from inside the earth, the flood waters rose more than 20 feet above the highest peak.
(center): Living creatures outside of the ark died from the flood but all that were in the ark were safe. [picture of ark]
(middle left): Once it stopped raining, the ark floated 150 days and nights. Then the ark came to rest upon a large mountain top.
(lower right): After living more than a year inside the ark, Noah sent a raven and a dove out to see if the earth was dry. The dove returned with an olive branch and Noah knew that soon it would be safe to return outside.
(lower middle): When Noah, his family and all the animals left the ark, a large beautiful rainbow appeared in the sky. The rainbow signified God's promise that the earth would never again be destroyed by water.
(lower left): Noah took about 100 years to build the ark. Noah was 600 years old when it was completed and 950 years old when he died.

Separation of Church and State, anyone?

I'm trying to figure out some of the odder details. The conversions of cubits to feet is a little haphazard, but not surprising in a child-oriented setting. I don't remember ever hearing about the ark being soundproof before, though, nor that Noah stocked the ark in seven days, after spending a century building it (My JPS version of the text suggests a bit less than a year inside the ark, not a bit more, though). There seems to be some particular tradition here that I'm not familiar with, or else it's both unconstitutional and incompetent.