Who Sank the Boat?
Inquiry activity based on the book by Pamela Allen
Created by Shawn Reintjes, The Science House, NCSU

 Who Sank the Boat? Followup Activity - Buoyancy

Exploration

Floating and Sinking:

  1. Find 20 items from your environment (at home, in your classroom, or outside).
  2. Sort the items into two separate piles; those you think will sink and those you think will float.
  3. Create a spreadsheet using Excel to record your predictions. Save the spreadsheet according to your teacher’s directions. Predict which items will sink and which will float. Record your predictions.
  4. Get a large container of water and test each item one at a time, by placing them into the bucket/bowl of water. Place a check mark by those items that you predicted correctly.

Question and Analysis:

  1. What do you notice about items that float? What do they have in common? What is different?
  2. What do you notice about items that sink? What do they have in common? What is different?
  3. Did any items seem to both float and sink?
  4. Can you modify any of your collected items that sank and make them float?
  5. Can you modify any of your collected items that floated and make them sink?
  6. What conclusions can you make about what sinks and what floats from your observations so far?
  7. What new questions do you have?

Whatever Floats Your Boat!

    1. Using a 20cm x 20cm square of aluminum foil, design and build a boat that will float on the water and carry a load of pennies.
    2. Mass (or weigh) your boat on a scale and record the number in your data table.
    3. Mass one penny and record this number in your data table.
    4. Estimate how many pennies can be loaded in your boat without sinking the boat. Record this amount in your data table.
    5. Place your boat in a large container of water. See if it floats! If not, reshape it and try again.
    6. Place one penny at a time into the boat until you reach a point where you add a penny and the boat sinks. (Hint-Remove the last penny, then count the remaining pennies in the boat and multiple this number by the mass of one penny. Add this number to the mass of the boat and record in your data table.)

DATA TABLE:

 

Mass of aluminum foil boat

g

Mass of one penny

g

Estimate of the mass of pennies that the boat can hold without sinking

g

Number of pennies that can be added to the boat without sinking

 

Actual mass of pennies that can be added to the boat without sinking

g

Mass of boat and pennies that remain floating

g

Share your answers with the class. The teacher will record your data in a class data table.

Questions and Analysis:

  1. Did some boat designs perform better than others (according to our class data)?
  2. How is the winning boat designed? Draw a picture of it.
  3. Why do you think it could hold more pennies?
  4. Did how you loaded the pennies on the boat make a difference? What is the best technique for adding pennies to a boat?
  5. How did your estimate and actual number of pennies compare?
  6. How many grams of water does your boat plus pennies displace when your boat is floating at maximum load capacity? Design an experiment to find out.

Applying What You Know to the Problem: So, Who Sank The Boat?

Now we need to design an experiment to help us answer our main question, “Who sank the boat?” We used pennies of the relative same size and weight in our last experiment, but the animals that got into Mr. Peffer’s boat were not the same size and weight at all!

There were five animals that wanted to ride on Mr. Peffer’s boat: a cow, a donkey, a sheep, a pig and a mouse. How much do you think an average one of these animals would weigh? Do some research and find out. Create a table with each animal listed and their average estimated weights. (Don’t just guess! Use data you gather from reliable sources to make your estimates.)

Animal

Average weight in pounds

Average Estimated Weight in Kg

Cow

 

 

Donkey

 

 

Sheep

 

 

Pig

 

 

Mouse

 

 

*Note: you may need to convert pounds to kilograms. If so, use the online metric converter at:
http://www.sciencemadesimple.com/weight_conversion.php

It is now time to set up an experiment so you can answer the question, “Who sank the boat?” First you will need to create models to represent the mass or weight of each animal. You will use small bundles of pennies held together with a small piece of plastic wrap. Since you obviously cannot make a model that weighs 700lbs., you will have to scale the model down to fit in your boat. You will scale your models for weight only.

Answer the following questions:

  • What is the total estimated weight of all five real-life animals?
  • What is the total number of pennies your boat held before sinking in Part 2?
  • What was the average estimated weight of each animal?
    • Cow-
    • Donkey-
    • Sheep-
    • Pig-
    • Mouse-

You will then create bundles of pennies in scale with the weights of the actual animals. To do this we will create a proportion based on the actual mass of the animals and the total number of pennies you found that would fill your boat without sinking (use number in data table #2 for this).

Use the following formula to calculate the number of pennies to place in each bundle to represent each of the five animals. (p.= pennies)

Est. wt. of 1 animal (Kg)
= X (# of p. in the bundle)
Total est. wt. all animals(Kg)
Total # of p. boat held

Fill in the table below with the correct information:

Example:

Cow 408(Kg) = X (p)

773(Kg) 265(p)

773X= (408X265)

773X=108,120

X=108,120/773

X=140 pennies

 

Animal

Avg. Weight in kg

Number of Pennies

Mass of each bundle of pennies

Cow

 

 

 

Donkey

 

 

 

Sheep

 

 

 

Pig

 

 

 

Mouse

 

 

 

Total Mass

 

Total Pennies

 

 

Once you have this information, go ahead and create your penny bundles to represent the cow, donkey, pig, and sheep. What can you use to represent the mouse?

Is the mouse’s mass even significant?

Conduct your experiment again and add your penny bundles to your boat one at a time. What happens? Can you now explain who sank the boat?

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