# Floating Stone Float or Sink Experiment
> Kids predict whether everyday objects will float or sink, test them in a tub of water, and then meet a surprise: a pumice 'stone' that floats. Finish by sorting everything into labeled Float and Sink jars.
- URL: https://www.funlittles.com/science-experiments-for-kids-floating-stone-experiment/
- Ages: 3–7 yrs · Difficulty: easy · Mess: medium
- Time: prep 15 min, activity 20 min
- Works for: one-on-one, small group, whole class · one batch serves about 2 kids
- Skills: science, float-and-sink, predicting, observation, sorting
- Cautions: corn, ingestion-risk

## Materials (one batch)
- 1 piece Bath pumice stone
- 1 piece Simple round container (clear tub or bowl) (household)
- Water (household)
- Pom poms
- Leaves (household)
- Twigs (household)
- Stones (household)
- Pebbles (household)
- Gravel (e.g. colored aquarium gravel)
- Popcorn (household)
- Raisins (household)
- 1 piece Bell
- Feathers
- 2 piece Jars (household)
- Tape and marker for labels (household)
- 1 piece Divided tray for setting out materials (optional) (household)
- 1 sheet Sink or float printable (optional) (household)

## Substitutions
- Instead of jars: Clear plastic jars or cups (Not from the post. A conservative swap so little hands aren't handling glass.)

## Safety
- Small test objects (popcorn, raisins, pebbles, gravel, pom poms, bell) are choking hazards. Supervise closely, and leave them out for kids who still put things in their mouths.
- Popcorn and raisins are test objects here, not a snack. Don't eat them after they've been in the water.
- Always supervise children around a container of water, even a shallow one.
- The post uses glass jars for sorting. Glass can break, so an adult should handle them or use clear plastic jars.
- Wipe up splashes so no one slips.

## Before you start
- Label two jars 'Float' and 'Sink'.
- Gather leaves, twigs, stones and pebbles from outside.
- Optional: print a sink or float record sheet for each child.

## Steps
1. Fill a simple round container with water.
2. Set out the test materials: pom poms, leaves, twigs, stones, pebbles, gravel, popcorn, raisins, a bell and feathers.
3. Pick one object and guess: will it float or sink?
4. Drop it in the water and check whether your guess was right.
5. Keep guessing and testing until every object has had a turn.
6. Feel the pumice 'stone' and predict what it will do, just like the other stones.
7. Put the pumice stone in the water and watch it float.
8. Try pushing the stone to the bottom and watch it come back up.
9. Look closely: most of the stone is under the water, and only the top sits above the surface.
10. Sort the materials into the 'Float' and 'Sink' jars and keep watching them.

## Tips
- We used a wide variety of materials to see the contrast.
- The popcorn was their favorite.
- Hold the pumice back until the end. The word 'stone' sets kids' minds on 'sink', especially after the other stones and pebbles have gone straight to the bottom, so it feels like a magic stone when it floats.
- Why it floats: pumice is a highly porous material made of volcanic ash. Its air cavities make it really light. Left in the water for a long time, water fills the cavities and it eventually sinks.
- We didn't use an observation sheet, but a simple printable (the author likes Buggy and Buddy's) lets kids record their predictions and results.
- Repeat the experiment later with new materials to see what the kids remember about the different variables. (from readers)

## The original post by TurkeyMom (2014)

Set up the classic float or sink science experiment with a twist When they are not being tested, I guess every single child loves science and loves experiments. Their innate curiosity is being nurtured when they are given the freedom to observe, experiment and predict.With this classic float or sink science experiments kids love to experiment the concept with utmost joy. Today's float or sink science experiment has a small twist though. I included a new material! Materials We used:

- **[Pumice Stone](https://www.amazon.com/dp/B003SZ4C1W/?tag=blmemo-20)**
- Pom Poms
- Leaves
- Twigs
- Stones
- Pebbles
- Popcorn
- Bell
- Raisins
- Feathers
- Gravel

We used a wide variety of materials to see the contrast.
 I used a simple round container and filled it up with water and set out the materials pictured above. We really did not use a observations sheet or any printable. I love this simple [**printable**](http://buggyandbuddy.com/science-for-kids-sink-or-float/) by Buggy and Buddy!  The kids enjoyed first guessing whether the object will float or sink and immediately compared their predictions with the actual results. The popcorn was their favorite.  Then I introduced this fun material. A bath pumice "stone". The word "stone" kind of set their mind with the "sink" answer. Both the kids felt it and decided that the "stone" will sink just like the other stones and pebbles that went straight to the bottom of the container.  Here is the product link for the "stone" But to their surprise this "stone" floats. Yes, it floats for a long time and the kids tried pushing them down to the bottom but it would come back up. However if you observe a large part of the stone is submerged in the water while the top part still is above the surface of the water. But to kids this "magic" stone is floating.  The pumice stone is a highly porous materials made of volcanic ash. The presence of air cavities makes it really light and it floats for a while. Leaving the stone in the water for a long duration makes the water enter the cavities and it does eventually sink to the bottom.  Later I set out 2 jars with labels on them and the kids sorted the materials into the jar for extended observation. 

Thanks for reading

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