Could a stack of hardcover books float if sealed in plastic wrap?

Ah, the eternal question for bibliophiles facing hypothetical floods, or perhaps just pondering bathtub physics! It conjures a rather comical image, doesn't it? A neat stack of hefty hardcovers, perhaps your prized collection of vintage encyclopedias, swaddled tightly in cling film, bobbing serenely upon the waves. But could this peculiar literary life raft actually float?

Let's dust off a little bit of delightful science, shall we? It all comes down to our dear friend, buoyancy, famously sussed out by Archimedes during his legendary bath. An object floats if it's less dense than the liquid it's placed in. More precisely, it floats if the weight of the water it displaces is equal to or greater than its own weight. Water has a density of about 1 gram per cubic centimeter (or 1000 kg per cubic meter, if you prefer). Things less dense than this float; things denser sink ( Physics LibreTexts ).

Now, consider Exhibit A: a lone hardcover book. It's made of paper, cardboard, glue, ink – all materials denser than water on their own. Drop it in the tub (please don't, unless it's already ruined!), and it heads straight for the bottom like a particularly well-read stone. The overall density of the book is greater than water ( Physics LibreTexts ).

So, where does the plastic wrap come in? It isn't about making the books themselves lighter, of course. The magic ingredient, the potential floatation device here, is air. Air is fantastically light, with a density far, far lower than water (around 0.0012 g/cm³). If you could wrap your stack of books in such a way that you trap a significant amount of air inside the plastic wrap, along with the books, you change the equation.

You're no longer calculating the density of just the books, but the average density of the entire package: books + plastic wrap + trapped air. If you trap enough low-density air, the average density of the whole bundle could potentially dip below the density of water. Voilà! Theoretically, your book-bundle boat would float ( Physics LibreTexts ).

The Devil's in the Details (or the Wrapping)

Ah, but theory and practice often diverge, like a poorly plotted novel. The enormous challenge here lies in the execution. Let's examine the practical hurdles:

• The Impermeable Seal: This is the absolute crux of the matter. Plastic wrap is designed to cling, yes, but creating a truly watertight, hermetic seal around an irregular object like a stack of books is incredibly difficult. Water is insidious; it will exploit any microscopic gap, any imperfectly sealed edge. Even a tiny leak allows water to seep in, displacing the precious trapped air. As air escapes and water enters, the average density increases, and your buoyant bundle begins its inevitable descent ( Physics LibreTexts ).
• Sufficient Air Volume: You need to trap not just some air, but enough air to offset the books' weight. The volume of trapped air required depends entirely on the weight and volume of the books. Wrapping tightly might seem secure, but it minimizes trapped air. Wrapping loosely traps more air but makes achieving that perfect seal even harder ( Physics LibreTexts ).
• Structural Integrity: Standard kitchen plastic wrap is thin and easily punctured or torn. The pressure of the water, handling the bundle, or even a sharp corner on a book cover could compromise the wrap, leading to catastrophic leakage.

So, How Do You Float Your Library?

If you genuinely needed to make books float (say, during an emergency, though hopefully, you'd prioritize saving yourself first!), relying solely on plastic wrap is a poor strategy. What works? Purpose-built waterproofing:

• Proper Containers: Think sturdy plastic totes with gasket seals, or specialized dry bags used by boaters and campers. These are designed to keep water out effectively.
• Dedicated Flotation: Inside such a container, you could include actual flotation aids – blocks of foam, sealed empty plastic bottles, or even inflatable bladders – alongside the books to guarantee positive buoyancy ( OpenStax College Physics ).
• Vacuum Sealing (Maybe?): While vacuum sealing removes air (bad for buoyancy inside the bag), a perfectly sealed vacuum bag is waterproof. If the bag itself plus the books were somehow less dense than water (unlikely without extra flotation), it could work. But the primary function there is waterproofing, not floating.

In conclusion, the image of plastic-wrapped books bobbing merrily is mostly a flight of fancy. While the physics allow for the possibility if enough air is perfectly sealed in, the practical reality of achieving that with standard kitchen wrap makes it highly improbable. It's a fun thought experiment illustrating the principles of density and buoyancy, but when it comes to protecting your literary treasures from water, stick to reliable, purpose-made solutions. Keep 'em high, keep 'em dry!