Best for this moment
for calmer, lower-pressure moments, especially when you need an indoor option.
Sink or Float Experiment
At a glance: Test which household objects sink or float in water. A 12-minute, low-energy indoor activity for ages 2y–4y.
A hands-on science activity that introduces cause and effect while keeping toddlers engaged. Making predictions before each item enters the water is an early scientific thinking skill, and the surprise when something does the unexpected sparks genuine curiosity. This activity naturally builds vocabulary as children describe what they observe and compare different objects.
Parent tip
Set out balls and plastic containers before inviting your toddler in so the first minute feels smooth.
What success looks like
A good outcome is a few minutes of engaged play, some back-and-forth with you, and a small sign of progress in cognitive skills.
More help for this situation
Rainy-day indoor energy
Rainy day
When everyone is stuck inside, choose movement-heavy play that burns energy without chaos.
Try Pillow Path AdventureInstructions
- Fill a large bin or bathtub with water
- Gather 8-10 safe household items: spoon, sponge, toy car, ball, rock, cork, crayon
- Before each item goes in, ask: 'Will it sink or float?'
- Let them drop it in and observe
- Talk about what happens: 'Look! The rock went down—it sank!'
- Sort items into 'sink' and 'float' piles afterward
- Let them predict and test new objects
- Lay towels down for spills
Why it helps
Making predictions before testing introduces scientific thinking and cause-and-effect reasoning. Describing what happens builds vocabulary and observation skills. Handling different objects also provides varied sensory input through weight, texture, and temperature.
Variations
- Try the same experiment with different liquids like salty water to see if results change.
- Use a clipboard and help your toddler draw a tick or cross for each prediction.
- Test items from outside — leaves, stones, sticks, and flowers.
Safety tips
- Never leave a toddler unsupervised around water.
- Ensure test objects are safe — no sharp edges or small parts that could be swallowed.
- Lay towels around the bin to prevent slipping on spills.
When to pause and seek extra support
Stop if your child becomes distressed, unsafe, or consistently frustrated by the activity. If play, behaviour, or development worries keep showing up across settings, check in with a qualified professional.
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