Sink or Float Challenge!

Learning Guide

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

Mai’s Tips

1. Use a clear container for the water so your child can easily see the objects from the side and top.
2. Encourage your child to feel the objects in their hands before putting them in the water. Ask if they feel heavy or light for their size.

Prep Before Session 5 min

• Collect 5-7 small, safe household items for testing (e.g., a coin, a small toy, a leaf, a sponge).
• Place all materials in the lesson area.

Photo by Karen Laårk Boshoff on Pexels

1Introduction 5 min

• Begin by sparking your child's curiosity about objects and water. Ask them about their personal experiences with water, such as playing with toys in the bath or seeing boats. This helps connect the science to their everyday world and makes it more relatable. Use open-ended questions to encourage them to share their thoughts and observations.

  * "Have you ever played with toys in the bath?"

  * "What happens when you put a rubber ducky in the water?"

  * "What do you think happens to different things in water?"

  Listen to their answers and affirm their contributions. The goal is to get them engaged in conversation and show initial curiosity about how different objects behave in water. They are the super scientist today!

Know Before You Teach

• Good to know: A 'rubber ducky' floats because it's often hollow and traps air.
• Connecting science to everyday life makes learning more meaningful for children.
• If they ask: Why does water make things float or sink? That's a super science question! We'll explore that today by seeing what different things do in water.
• It's working when: Child responding with examples from their own experience or showing excitement about water.

• If they're stuck: Show a picture of a boat on the water and ask what they think about it.
• Easier: Ask only one simple question about playing in water.

Done when: Student engages in conversation and shows curiosity about objects in water.

Photo by Jan van der Wolf on Pexels

2Explore & Plan 8 min

• Gather the materials for the experiment: a large bowl or tub (a clear one is best to see the action!), water, and 5-7 small objects from around the house. Fill the bowl with water. Explain that you will be making predictions, which are your best guesses about what will happen. Have them choose an object to start with.

  * "Which object do you want to pick first?"

  * "What's your very best guess for this object?"

  * "Do you think it will float or sink?"

  Introduce the terms: Float means it stays on top of the water, like a boat. Sink means it goes down to the bottom, like a pebble. We make predictions so we can test our ideas and learn from them.

  Done: Complete this stage when all materials are ready and they have made at least one prediction for an object.

Know Before You Teach

• Good to know: Making a prediction means you are making your best guess before you try something.
• Scientists make predictions to help them think about what might happen.
• Gathering materials together is the first step in many science experiments.
• If they ask: Is my guess right? It's a great guess! We'll find out if it's right when we test it later.
• If they ask: What if I don't know if it will float or sink? That's okay! Just make your very best guess, even if it feels tricky.

• Key words: Float: When something stays on top of the water, like a leaf.
• Key words: Sink: When something goes down to the bottom of the water, like a coin.
• It's working when: Child pointing to an object and using the words 'float' or 'sink' with confidence.
• If they're stuck: Model making a prediction for one object yourself, saying 'I predict this will sink because it feels heavy.'
• Easier: Offer only two very different objects (e.g., a sponge and a metal spoon) for the first prediction.
• Harder: Ask them to group all the objects into 'floaters' and 'sinkers' categories before any testing.

Done when: Student has gathered materials and made at least one prediction for an object.

Photo by MART PRODUCTION on Pexels

3Discussion 6 min

• Once your child has made a prediction, encourage them to explain their reasoning. This stage focuses on thinking skills rather than right or wrong answers. Prompt them with questions that help them articulate their thoughts and connect them to the object's properties. Have them feel the objects in their hands before putting them in the water.

  * "Why do you think that feather will float?"

  * "How does that object feel in your hand?"

  * "Does it feel heavy or light for its size?"

  * "What makes you guess that?"

  Listen actively and affirm their ideas, whether they seem logical or not. The value is in the thought process and observation, not the accuracy of the initial guess.

  Done: End this stage when the child can explain their reasoning for at least two predictions.

Know Before You Teach

• Good to know: Objects that are lighter for their size often float, while objects that are heavier for their size often sink.
• Air trapped inside an object can help it to float, even if the object itself is heavy.
• A scientist's reasoning helps them understand why things happen, not just what happens.
• If they ask: Is my reason good? Yes, that's a great way to think about it! Thanks for telling me your idea.

• It's working when: Child using descriptive words like 'heavy,' 'light,' 'big,' or 'small' to explain their prediction.
• If they're stuck: Hold up a very light object (like a feather) and a very heavy object (like a rock) and ask, 'Which one do you think will float?'
• Easier: Simply ask, 'Why do you think that?' without prompting about specific properties.
• Harder: Ask them to explain how one object's characteristics are different from another's, and how that relates to their prediction.

Done when: Student can explain their reasoning for at least two predictions.

Photo by Arthur Krijgsman on Pexels

4Activity 9 min

• It's time for the grand experiment! Supervise your child closely during this water activity to ensure safety and minimize mess. Have them gently place their first chosen object into the water. Encourage them to observe closely and describe what they see.

  * "What happened when you put it in the water?"

  * "Did it float, or did it sink?"

  * "What do you see happening to the object?"

  * "How is this object different from the last one?"

  Remind them to be great observers. Avoid correcting predictions; the learning comes from the observation of what actually happens. Take pictures of their discoveries!

  Done: Continue testing until the child has placed at least 3-4 objects in the water and observed what happened to each.

Know Before You Teach

• Good to know: Water pushes up on objects, which is a force called buoyancy.
• Some objects might float at first but then sink as they get wet and absorb water.
• Careful observation helps scientists see exactly what happens during an experiment.
• If they ask: Why did it do that? That's what we're trying to figure out! What did you notice about how it looked or felt?
• If they ask: Can I splash? Let's try to be super careful scientists today and gently place things in the water.

• It's working when: Child leaning in to watch the object, pointing, or exclaiming about what happened.
• If they're stuck: Gently place one object in the water yourself and narrate exactly what you see it doing.
• Easier: Ask only 'Did it float or sink?' after each object is placed in the water.
• Harder: Ask them to compare what happened to the current object with what happened to a previous object.

Done when: Student has tested at least 3-4 objects and observed what happened to each.

Photo by Takuya Hozumi on Pexels

5Summary 2 min

• Celebrate your child's efforts and discoveries as a scientist today! You made predictions, tested them, and watched so carefully. Reinforce that observation and testing are important parts of science. Ask reflective questions to help them summarize their learning and identify what they found most interesting.

  * "What was something new you learned today about water and objects?"

  * "What was your favorite object to test, and why?"

  * "What surprised you the most about what happened?"

  Encourage them to recall the terms 'float' and 'sink' and give examples from their experiment. Affirm their hard work and careful watching.

  Done: Finish this stage when the child shares at least one key takeaway or observation from the activity.

Know Before You Teach

• Good to know: Learning comes from trying things and watching closely, even if your first guess was different.
• If they ask: Can we do it again? We can try it again with new objects another time!
• If they ask: Why did that one float, but this one sink? That's a very thoughtful question! Maybe we can explore that next time.
• If they're stuck: Point to one object that surprised them and ask, 'What did this one do, and why do you think it surprised you?'
• Harder: Ask them to draw or describe what they learned about objects in water today.

Done when: Student shares one key takeaway or observation from the activity.

Your Notes