Investigating the capacity of lifeboats.

  

Before we began our investigation, students discussed what they knew about lifeboats. The most common response was that they were used on the Titanic and aided people to safety. Lets all thank James Cameron for the prior knowledge!
The investigation started with a "BIG Question." What variables might affect how many passengers a boat can hold? For our investigation we used a paper cup and pennies to serve as boats and people. Each boat measured 3cm. The students ran two sets of three trials. Pennies were placed in the cup (boat) until it sunk. Each group then shared their results. We had anywhere from 6 pennies to 28 pennies. Why were the results so different if all boats were the same? This question brought us back to our BIG Question. Students listed the following as possible variables for boat capacity:
-Loading procedure (how the pennies were placed in the cup)
-Size of boats
-Water conditions
-Type of coin
In the second set of trials, we changed one variable. All boats needed to have a standard loading procedure. The pennies were placed carefully, one at a time, and balanced. The results seemed to be more consistent but differences still existed. Were the capacities for each boat really the same? To determine the capacity for each boat we used a graduated cylinder (ml) and a syringe. Three out of the two boats had different capacities. The students decided there might have been complications in the building process (boat was smaller or bigger than 3cm). How does this investigation relate to deciding the construction and capacity of a real boat?

What connections can you make with our investigation?
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