Materials and Tools Clear storage tubs to test submersibles in water (buckets or full sinks will also work) Rags and paper towel Building materials that float or sink, e.g. balloons, paddle pop sticks, wooden skewers, dowel, PET bottles, plasticine, straws, pipe cleaners, CDs, nuts and bolts, paperclips, pipettes, cotton reels, plastic or polystyrene cups, core flute, anything else you have in large quantities Water resistant joining and sticking materials (hot glue, string, twisty ties, rubber bands etc.) Scissors Extension materials: syringes & plastic tubing to fit (these can be substituted with a submerged balloon and a straw to fill it with air), aspirin tablets, magnets Lesson Outline – 120 minutes The below lesson outline provides an overview of workshop elements. Please ensure you follow your school WH&S procedures while conducting this lesson. Introduction (10 minutes) Introduce the Innovation Process, tools, materials and workspace. The challenge will be introduced in stages. You might like to begin by introducing a few basic ideas about buoyancy i.e. density. See our short activity “Does Fruit Float.” You may choose to discuss some examples of submersibles (i.e. Deepsea Challenger). Buoyancy discovery (5 minutes) Lay out all the building materials on a table. Challenge 1: Scavenger hunt. Ask students to find three objects that they believe will float, three objects they believe will sink and three objects they’re not sure about. Ask students to test their predictions in the tubs of water. Discussion: In small groups or as a class, students discuss their findings (i.e. What were their predictions? Which discovery surprised them?) Buoyancy application (15 minutes) Instruct the students to split into groups of 2-3. Challenge 2: Build a raft. Ask students to build a vessel that floats using at least some of the objects they tested in the scavenger hunt. Students may wish to supplement building materials with more building supplies.
Negative buoyancy discovery (10 minutes) Challenge 3: Sink your raft. Challenge students to now submerse their floating vessel. Many will add materials that have negative buoyancy to counteract the materials with positive buoyancy. Discussion: You may wish to discuss other methods of making the rafts sink (e.g. putting a hole in the hull, changing orientation). Neutral buoyancy discovery + application (40 minutes) Once the students have sunk their vessel, introduce the concept of neutral buoyancy (objects that neither float nor sink but maintain a fixed position in the water column). Some real life examples include fish swim bladders, and SCUBA divers’ buoyancy control devices. Challenge 4: Neutral Buoyancy. Challenge students to make their vessels neutrally buoyant Helpful tip: Achieving neutral buoyancy is difficult and may take significant tinkering. If students are struggling, you can them a syringe filled with air as a swim bladder. This makes fine tuning their submersible relatively easy by adding or subtracting small volumes of air. Extension Activities (allow 20+ minutes for group success) are a number of extension activities that can be tailored to the individual groups and their designs, such as: Controllable buoyancy: Introduce a second syringe or some aspirin and challenge students to create a submersible that floats or on command Introduce fluids of different density e.g. oil – to be used in the submersible Wrap up (Allow 25 minutes for reflection and pack up) Design Sharing: Share design approach, successes and challenges, and encourage class reflection as a group. Facilitate questions and discussion on workshop, including: Was testing important during the design What would you do differently next time? If you were to this full scale what materials could you use? Submersible deconstruction: recycle as much material as possible. Further Investigation Real-world examples that face the challenges of neutral buoyancy include NASA’s Neutral Buoyancy Laboratory, and Australia’s Deepsea Challenger (videos available on YouTube using search terms and ). Students can investigate the advantages and disadvantages of the different submersibles, including remotely operated vehicles (ROVs), autonomous underwater vehicles (AUVs) and human occupied vehicles (HOVs).