Download STEM Lab #2: Penny Boat Challenge

STEM Lab #2: Penny Boat
Challenge
The Challenge:
A food manufacturer needs a ship to deliver their
products overseas. To save money on fuel, the
manufacturer is looking for the ship design that will
safely transport the most crates of food (pennies)
per trip. To be considered safe, your ship must float
for at least 1 minute with the crates of food.
Your job is to design and build a ship that can safely
carry the most food.
Materials
and
Rules
1. You can build up to 4 different boat
designs during this lab.
2. Draw all boat design in your lab
sheet and record the total number
of pennies held for each boat
design.
3. Each boat may only be built using:
a. one 15cm (6 inches) x 15 cm
square of aluminum
b. no more than 2 straws
c. 8 inches of clear tape
4. Total time limit: 30 minutes
5. Each group will be allowed one final
opportunity to redesign and build
their boat in the lab on Friday.
Penny Boat Follow-up Discussion
→ Spend 3-4 minutes with your group reflecting on your different boat designs from the Penny
Boat Challenge, and be prepared to share your ideas with the class. Be sure to discuss the
following:
A. Design features that worked well
C.
How did you use the straws and tape?
A. Design features that didn’t work well
D.
What will you improve/change for your
final boat?
The Science of Penny Boats
Consider the density of the following:
substance
density
water
1.0 g/cm3
aluminum foil
2.7 g/cm3
a penny
7.2 g/cm3
So if pennies and aluminum foil are more dense than water, how
were the boats able to float, and in some cases hold as many as
75 pennies before sinking?
The answer is……….
Buoyancy!
➔ Buoyancy is the ability of an object to float in a fluid. It results from two opposing forces:
◆ 1. the force of gravity pushing DOWN on an object AND
◆ 2. the buoyant force: a force of fluids pushing UP on a floating object.
➔ When an object is put into water, it pushes aside or _____________________ a volume of
water equal to the object itself.
➔ Archimedes’ Principle says that the buoyant force is equal to the weight of water an object
displaces.
◆ If the weight of the water displaced is greater than or equal to the weight of the object, it
will float. ex 1: a cruise ship that weighs 50,000 tons will displace 50,000 tons of water
ex 2: a basketball pushed under water will float up to the surface because the weight of the
water it displaced was more than the weight of the ball.
◆ If the weight of the water displaced is less than the weight of the object, it will sink.
◆ If the density of water and the density of the object are near equal, the object will
neither float nor sink, and is “neutrally buoyant.”