1. STEM Lab #2: Penny Boat Challenge

2. 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. The Challenge:

3. 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.

4. Penny Boat Follow-up Discussion A.Design features that worked well A.Design features that didn’t work well C. How did you use the straws and tape? D. What will you improve/change for your final boat? → 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:

5. The Science of Penny Boats Consider the density of the following: 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………. substancedensity water1.0 g/cm 3 aluminum foil2.7 g/cm 3 a penny7.2 g/cm 3

6. Buoyancy! ➔ Buoyancy is the ability of an object to float in a fluid. It results from two opposing forces: Buoyancy ◆ 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.”