What Floats Our Boats? Exploring Density and Buoyancy
Just how does a massive ship, made of steel and wood, manage to stay afloat? The Orange Band began their explorations into the ideas of buoyancy and vessels at the Hyde Street San Francisco Maritime National Park Association. The kiddos had an opportunity to assist in the build of a Bevin's skiff (a small rowboat) and take a spin in a completed skiff out on the San Francisco Bay!
*Meanwhile, Back at the (Brightworks) Ranch*
The Orange Band was raring to get out on the water again - or at least begin boat construction of their own designs. But we had to take a giant step back before setting sail. Before we could jump into building boats in our shop, we needed to become familiar with the science behind what allows any substance float on water.So, the kiddos were presented with a series of items: ceramic, wood, steel, and plastic. Their task was to measure the volume and mass of each set of items, graph the data, and then compare that to water.
Once our measurements had been double and triple checked, kiddos graphed the data and observed four lines with very different slopes. Then the Orange Band measured and graphed the volume and mass of various amounts of water. With little deviation, the data collection revealed that water's volume and mass are equal in value!
This information, graphed, gave a clear picture of which items would float (wood, with a line slope smaller than water's) and which would not (any item with a line slope steeper than water's). The work gave the students an opportunity to see WHY we graph - and brought to light the formula for density (density = mass/volume) and its relationship to buoyancy. Next up? (Small) Boat Building!Next, kiddos were given a challenge: build a boat out of a 12" x 12" piece of aluminum foil that holds the MOST mass. While the constrictions of the challenge were met with some resistance (Couldn't we just add toothpicks? Or use some tape?), they provided an opportunity to work within controlled conditions and compare their results!
These forays into how vessels carry mass that is greater than the crafts, themselves, set the stage for the Orange Band's next explorations: What are the factors that affect the success of such crafts?Next on the docket: deeper dives into density and shape of hulls and ships.
