Lesson 142: Experiment — sink or float

Objective

I can do a simple sink or float experiment. I can predict what will happen, test my ideas with water, and record which objects sink and which float.

Materials

• Large clear bowl, basin, or sink half full of water
• Small objects that can get wet (for example: plastic spoon, metal spoon, rubber ball, coin, pencil, small block of wood, bottle cap)
• Simple table drawn on paper with columns: "Object", "Will it sink or float?", "What happened?"
• Towel for drying hands and objects
• Pencil or crayon
• Adult help for safety around water

Mini-lesson — What does sink or float mean?

Guided Practice — Try a sink or float test

You will choose a few objects, predict if they will sink or float, then test them in water with an adult.

1. Prepare the water: With an adult, fill a bowl or basin halfway with clean water. Place a towel nearby.
2. Choose objects: Pick safe objects that can get wet, such as a plastic spoon, metal spoon, small wood block, toy car, rubber ball, bottle cap, and pencil.
3. Make predictions: On your table, write the object name and write "sink" or "float" in the prediction column.
4. Test gently: With adult help, place one object at a time on the water. Watch what happens. Does it go to the bottom or stay on the top?
5. Record results: In the result column, write what really happened, using words like "sank" or "floated".
6. Talk about why: For one or two objects, say why you think they sank or floated. Use words like heavy, light, wood, or metal.
7. Use the tracing pad: Choose words like sink, float, water, or test and trace them. Say the word and a short sentence as you write, such as "The ball floats".

Tracing Pad

Lines Primary lines Baseline only Grid Blank Trace (none) sink float water object heavy light wood metal plastic predict test record

Pen Clear

Tip: As you trace, say a full idea like "Wood can float" or "The coin sinks in water".

Practice 1 — Predict and test

Use your table to write predictions and results for a few objects.

1. Draw a simple three-column table with headings: "Object", "Will it sink or float?", and "What happened?".
2. Choose at least five small objects. For each one, write the name in the first column.
3. In the second column, write your prediction: "sink" or "float".
4. Test each object in water with an adult and write what really happened in the third column.
5. Circle any objects where your prediction was different from the result and talk about why.

Practice 2 — Sort pictures into sink or float

Sort drawn or printed pictures into "Sinks" and "Floats".

1. Draw two big boxes on your page. Label them "Sinks" and "Floats".
2. Draw small pictures of objects such as a coin, stone, wood block, plastic bottle, paper boat, and rubber ball.
3. Think about each object. Where would you place it after a water test?
4. Write or draw each object in the box where you think it belongs.
5. With an adult, test one or two of the objects if it is safe. Check if your sorting was correct and move any that need to change.

Practice 3 — Explain your thinking

Use sentences to explain why some objects sink and others float.

1. Choose two objects that sank and two objects that floated in your experiment.
2. For each object, write one sentence that starts with "It sank because…" or "It floated because…".
3. Use simple ideas like "It is heavy for its size", "It is made of wood", or "It is full of air".
4. Read your sentences to an adult and see if they can tell which objects you mean.

Quick Check — Experiment: sink or float

Answer each question about sink, float, and water tests. Think about what you saw in your experiment.

Assessment (parent/teacher)

Exit ticket (student)