Float Your Boat!

Learning Guide

A simple guide to lead you through the kickoff, the core challenge, and everything in between.

Mai’s Tips

1. Encourage multiple iterations! The learning often happens when a design fails and the child has to figure out why and how to improve it.
2. Focus on asking 'what if?' and 'why?' questions during the activity to promote deeper thinking, rather than telling them how to build.

Prep Before Session 10 min

• Gather aluminum foil, small objects like marbles or pennies, and a tub or basin for water.
• Fill the tub with water and place it on a waterproof surface, with a towel nearby.
• Set out the foil and small objects close to the water.

Photo by Marion Pintaux on Pexels

1Introduction 5 min

• Start by asking the child about their experiences with water and objects. Encourage them to share initial thoughts without judgment. Ask: "Have you ever seen a big ship float on water?" or "What about a tiny pebble – what happens to it in water?" Introduce the terms `floating` and `sinking`. To float means something stays on top of the water, like a rubber ducky. It's the opposite of sinking. To sink means something goes down to the bottom of the water, like a heavy rock. It's the opposite of floating. Prompt their curiosity with: "What do you think makes some things float and others sink?"

  Done: Child has shared an initial idea or question about floating/sinking.

Know Before You Teach

• Good to know: Many large objects, like ships, can float, while small heavy objects, like pebbles, often sink.
• If they ask: Why do some things float and others sink? That's exactly what we're going to explore together today by making our own boats!
• It's working when: Child points to or describes something that floats or sinks from their own experience.
• If they're stuck: Show them a picture of a large ship on water and a small rock at the bottom of a pond to spark discussion.
• Easier: Ask them to just point to one thing in the room they think would float or sink if you put it in a bathtub.

Done when: Child expresses an initial thought or question about floating/sinking.

Photo by Polesie Toys on Pexels

2Explore & Plan 8 min

• Help the child gather the aluminum foil, small objects (like marbles or pennies), and a tub of water. Before building, challenge them to make a `prediction`. A prediction is your best guess about what will happen, based on what you already know or think. Ask: "What do you think will happen if you put this flat piece of foil in the water?" and "Why do you think that will happen?" Then ask: "What about one of our small objects? Will it float or sink?" Encourage them to briefly test their predictions to see what happens.

  Done: Child has predicted outcomes for the flat foil and a small object, then briefly tested them.

Know Before You Teach

• Good to know: A flat piece of aluminum foil usually sinks because it cannot displace (push aside) enough water.
• Small, dense objects like marbles or pennies typically sink due to their weight and density.
• Making a prediction helps us think about what we expect to happen before we try it.
• If they ask: Is it okay if my prediction is wrong? Absolutely! Scientists often make predictions that turn out differently, and that's how they learn new things.
• If they're stuck: Model a prediction yourself, saying, 'I predict the penny will sink because it feels heavy to me.'

• Easier: Just ask them to make a prediction about one object, like the flat foil, before testing it.

Done when: Student has predicted outcomes for basic materials and is ready to move to discussion.

Photo by Kirill Ozerov on Pexels

3Discussion 6 min

• Have the child share their `observations` from the initial tests. An observation is something you see or notice carefully. Ask: "What did you notice about the flat foil when you put it in the water?" and "What happened to the small object?" Guide them to think about how shape might matter for floating. Ask: "Do you think the shape of something matters for floating or sinking?" Help them connect their observations to the idea of floating and sinking.

  Done: Child has described their observations and started to connect them to the idea of floating/sinking.

Know Before You Teach

• Good to know: Changing an object's shape, even if it's the same material, can change whether it floats or sinks.
• It's working when: Child describes what happened to the flat foil and the small object without needing a specific prompt.
• If they're stuck: Ask concrete questions like, 'Did the foil stay on top or go to the bottom?' to help them recall details.
• Easier: Ask them to simply state one thing they noticed about either the foil or the small object.
• Harder: Ask them to compare what happened to the flat foil versus the small object and suggest why they might have acted differently.

Done when: Student can describe their observations and begins to connect them to the idea of floating/sinking.

Photo by Doğan Alpaslan Demir on Pexels

4Activity 9 min

• Encourage the child to design and build their own boat using the aluminum foil. The goal is to make a boat that can hold as many small objects as possible without sinking. Guide them to experiment with different shapes, reminding them that scientists learn from designs that don't work the first time. Ask: "What kind of shape do you think would be best for holding lots of treasures?" or "What if we made the sides taller or wider?" Once they have a boat, have them place it in the water and carefully add small objects one by one until it sinks. Ensure the play area is safe for water. `Buoyancy` is the upward force from the water that makes things float; a good boat has good buoyancy!

  Done: Child has built at least one foil boat and tested its ability to float with objects.

Know Before You Teach

• Good to know: Boats float because their shape allows them to displace (push aside) a lot of water, which creates an upward force.
• A boat's shape needs to hold air and create a larger surface area on the water for better stability and to hold more objects.
• If they ask: How come this boat sank so fast? It might have filled with water, or the shape wasn't pushing enough water away to hold all the objects; let's try a different shape!
• Key words: buoyancy: the push from the water that helps things float up

• It's working when: Child tries different boat shapes or modifies their boat after an initial test or failure.
• If they're stuck: Suggest they try making a simple bowl shape with the foil or folding up just the edges to create a rim.
• Easier: Focus on making any shape that floats, even if it can't hold many objects, emphasizing the achievement of floating.
• Harder: Challenge them to design a boat that can hold a specific number of objects, like 10 pennies, before it sinks.

Done when: Student has built at least one foil boat and tested its ability to float with objects.

Photo by William Liu on Pexels

5Summary 2 min

• Celebrate the child's efforts and discoveries in building and testing their boats. Ask them to reflect on their learning. Ask: "What was the most surprising thing you learned about floating and sinking today?" or "If you were to build another boat, what would you do differently?" Help them connect their exploration of `buoyancy` to the real world. Ask: "Why do you think a giant cargo ship can float, even though it's so heavy?" This reinforces that the same science applies to big ships and their foil boats.

  Done: Child shares one key takeaway from the activity.

Know Before You Teach

• It's working when: Child mentions that shape matters or connects their foil boat experience to real-world ships.
• If they're stuck: Prompt them by asking, 'What did you learn today about making things float?'
• Easier: Ask them to simply show you their favorite boat design they made today.

Done when: Student shares one key takeaway.

Your Notes