Clay Captains Teacher GuideClay Boat Challenge Teacher Facilitation Guide Objective Students will apply engineering skills to change an object's density and make a sinking object float. Duration 45 Minutes Total • Warm-up: 5 min • Video: 5 min • Activity: 20 min • Closure: 10 min Materials Per Student/Group: • Modeling clay (non-drying) • Large tub of water • Paper towels • Challenge Worksheet 1 Warm-up & Video (10 min) Play the Lighthouse Lab video. Focus on the segment starting at 1:57 where the clay ball is tested. Discussion Questions: "Why did the clay ball sink to the bottom?" (It is more dense than water). "Do you think there is any way we could make that same piece of clay float?" 2 The Challenge (20 min) Hand out a ball of modeling clay to each student. First, have them place it in the water to verify it sinks. Then, challenge them to reshape it so it floats. Engineering Tips: Thin it out: Encourage students to flatten the clay into a "pancake" and then pull the sides up. The Bowl Shape: Remind them that boats often have space for air inside. Leak Check: If their boat sinks, check for holes or cracks where water might be "sneaking in." 3 Testing & Closure (10 min) Gather the class around the water tubs to test successful designs. The "Why": By spreading the clay out and creating a hollow shape, we increased its volume (it takes up more space). This allows it to push more water out of the way, making it less dense than the water it sits on. Vocabulary Check: Density: How crowded an object is. Buoyancy: The upward push of water. Standards Connection NGSS K-2-ETS1-2: Develop a simple sketch, drawing, or physical model to illustrate how the shape of an object helps it function as needed to solve a given problem.
Lighthouse Lab SlidesEngineering Challenge Lighthouse Lab: The Clay Boat Can you make a sinking object float? Mystery of the Clay Think About It: Why do some objects stay on top of the water? What happens when we drop a heavy ball of clay into the water? Watch: Lighthouse Lab – Floating and Sinking Embedded media Watch closely at 1:57 - What happens to the clay ball? What is Density? Density is how crowded the stuff inside an object is. If an object is more dense than water, it will sink. High Density Low Density Which one sinks? Which one floats? Your Challenge Reshape your ball of clay into a shape that floats in water! Ready... Set... Build! Pro Engineer Tips Think Volume Make your clay take up MORE space than it did as a ball. Trap Some Air Boats use air to help them float. How can you trap air in your clay? No Leaks Watch out for holes! Even a tiny crack can sink a big ship. The Secret Science When you flatten the clay and pull up the sides, you create a larger volume. This "boat" pushes more water out of the way, which creates an upward force called buoyancy! Successful Design!
Clay Boat Challenge WorksheetClay Boat Challenge Design Portfolio Lighthouse Lab Name of Engineer: Date: 1 The Prediction What happens when you put a ball of clay in the water? It Sinks It Floats 2 The Engineering Sketch Before: The Ball Draw ball here Result: Sank After: The Boat Sketch your boat design My goal: make it float! 3 The Results Did your boat float? (Circle one) Yes! Almost Not yet How did you change the clay to help it float?
Lighthouse Lab Answer KeyFloating & Sinking Answer Key Lighthouse Lab Support Material Key Discussion Points Q: Why did the clay ball sink? A: The clay ball is more dense than water. All of its mass is packed into a small volume (space), making it "heavier" than the water it tries to push away. Q: How does the "boat" shape make it float? A: By spreading the clay out and pulling up the sides, we increased the volume (amount of space it takes up). This larger shape pushes more water aside. Because it is hollow and contains air, the boat's overall density becomes less than the water's density. Video Experiment Results Rubber Duck Float Bath Plug Sink Clay Ball Sink Metal Coin Sink Polystyrene Ball Float Ping Pong Ball Float Glass Marble Sink Wooden Block Float Success Criteria A successful clay boat design will likely have these features: Wide Base: Spreads the mass of the clay over a larger surface area of the water. High Walls: Prevents water from splashing in over the sides and filling the air pocket. Smooth Finish: No cracks or holes (water sneaks into cracks, increasing density). Lightweight Walls: If walls are too thick, the boat becomes too heavy/dense and sinks anyway. Word 1 Density Word 2 Buoyancy Word 3 Displacement
