toddler doing a science experiment
Exploring Floating and Sinking

Two truths: Preschool science is a thing of beauty and preschoolers love to eat snacks.  That makes exploring floating and sinking with snack time foods a preschool science experiment for curious little ones.  Your child gets to explore but you don’t really need anything fancier than a normal snack!

Little kids are born to be scientists!!! 

Truly, science comes so naturally to children because they spend their entire day learning and exploring through their own natural curiosity.  Making it an experiment on purpose is just an extension.  Their whole lives follow the scientific method that I’ve been teaching older kids for years!

Even the least scientific among us can do science with little kids.  They are doing it already all on their own!

Preschool Scientific Method

Think about it and you can watch science in action at any given time with kids.   

This is a preschool version I’ve made of the scientific method big kids learn about at school.  How often have you seen your child do exactly this cycle? 

Probably loads of times!!

preschool science experiment cycle: question, guess, experiment and think

For example, we went to a new playground this morning.  I watched my 2 year old look at a new obstacle of pretend tree stumps as a way to get down from a platform and could imagine this little thoughts going through this cycle exactly based on his actions!!

Ask a Question:

He tilted his little head to the side obviously thinking about what to do: “Can I do that?” and “Can I reach?”


He must’ve guessed he could make it to the first stump because he grabbed the bars at the opening and started to step out – much to this mama’s worry because it was actually a bit high and I wasn’t sure it was small enough a gap!!

Experiment & Explore:

He did a couple little tries first with one foot then the other, but obviously wasn’t as able as he originally thought.

Think About It:

He stopped and looked again (head tilted again – so cute!) because his first idea didn’t work.  It was too far for him to step out and reach.  This usually leads to more questions and the whole things starts again!  In my son’s case his new question must have been “Will it work if I do it backwards on my belly like stairs?” because I had to cut this experiment short by grabbing him instead of letting him dangle over the edge on his belly! Yikes!

Now you just add in a little bit of on purpose experimenting with a few key concepts explained so kids understand and voila – every mom is the most awesome science teacher!""

Exploring Floating and Sinking With Food

Maybe as the mom I should say “Don’t play with your food!”, but snack time science experiments really are the perfect opportunity for observing different things because it’s pretty easy to get an assortment of foods to test!

The premise of this experiment is SUPER EASY but loads of fun for the kiddos. 

You basically do nothing more than you normally would for snack, but it becomes a whole big fun preschool learning activity letting your child spend time freely exploring sinking and floating!  The best kind of mom win!

And bonus for picky eaters – it makes the food more interesting and might get more eaten – just like this snack time game I wrote about in another post!

The Perfect Preschool Science Experiment:  Exploring Sinking and Floating

This is a great preschool or toddler science experiment that we basically do at least once a month here because:

  • it is easy
  • so many observations to take
  • lots of connections to make
  • always new questions to consider so
  • you can do it over and over



You don’t need anything fancy for this easy preschool experiment.  All you need is:

  • a clear cup or glass with water in it
  • any food you want that’s a mix of floating and sinking

By switching up your materials you can actually do this experiment over and over again and have it be new and exciting every time!

food for snack time science grapes, cheese, cucumber, marshmallows and sprinkles

For some ideas, here’s what we used to start this experiment:

  • grapes
  • marshmallows
  • sprinkles
  • cucumber
  • cheese
  • white chocolate chips

A totally random assortment – use whatever you have that is a mixture of heavy and light!!

Try this magnetic fishing game science activity too!!

How to Do This Simple Experiment:

  1. Fill a cup 3/4 full with water.
  2. Just start dropping things in, letting your child explore and have fun with zero structure whatsoever.  NO structure is 100% excellent at this age!! My 2 year old loved it this way – plus eating everything out of the cup! Yes, even the soggy piece of bagel – yuck!toddler science dropping food to sink or float

If your kiddo is a little older and/or more willing to slow down, a bit more structure is great to help guide simply analysis and connections.

Drop one food item at a time but pause first to guess what will happen and also record what you actually see happen like described below.  It adds a bit more science on purpose with just a few little prompts from mom. 

Again, you don’t need to know any science though! Keep reading for some simple prompts and you can have fun learning together.   

Sink or Float Experiment Observations:

This is the perfect simple experiment for pretending to be a scientist recording observations. 

This is my 4 year old writing an F or S beside each food I sketched.  This also had the huge added bonus of giving her a chance to practise the letter S!  It’s a tricky one that usually ends up backwards and it’s in her name so double win for sneaking that in here!

child recording science observations

No letters yet? No problem, here are other options:

  • Draw an arrow up/down
  • Scribble on a picture of a cup where the food ended up
  • Thumbs up or thumbs down
  • Stand up tall or squat down low – this one’s great for kids who don’t want to stay still to observe!   

Preschool Science Analysis:

It’s the perfect simple toddler experiment for observing something simple, but then getting your toddler to think about WHY something happened! 

Cup of water with food sinking and floating experiment

Instead of just leaving it at yep, it sank or hey look, it floated ask some simple follow up questions! 

You don’t need to know the answers.  It’s even more fun to learn together!

Great Questions to Chat About With your Preschooler:

Why do you think it sinks for floats?

Depending on your child’s answer test the theory!  That’s the whole point of science – you don’t need to know the answer, you’re exploring sinking and floating.  Exploring means open-ended!! 

Do all big things sink and small things float?  

Try a big thing you know will float (like a chip) and a small think you know will sink like a piece of cheese.  Or better yet, try a big piece of cheese and a small piece of cheese.  That way the size is the only difference so it is really what’s being tested!  This is also a good time to mention that boats are really big but they float!

Does the shape make it sink or float?

This is a natural follow up to the size question.  Cut a food in different shapes, try something round and something square.  

Does how you drop it matter?  

Take the exact same item and drop it from up high and down low.  Drop something that has different sides facing up and facing down.

Does it always float?  

Leave a food item for awhile and see if anything changes.  Some food absorb water and so will end up sinking after awhile. 

Preschool Science Experiment Data Sheet


Exploring Floating and Sinking Science:

Basically it all comes down to buoyancy.  Is the buoyant force of the water pushing up on the food more than the force of gravity puling it down?  These forces depend on the density of the fluid and the mass (therefore density) of the food being tested.  

Yes, a lot more complex than a toddler needs to know, but if you want to check it out, here’s a good simple buoyancy explanation

My kids love science (and so do I), so even if they won’t get it all it’s fun to look at explanations!

Want More Fun Preschool Science???  Bonus Preschool Buoyancy Experiment:

1: Fill 3 glasses with water.

2: Put 4tbsp salt in the first glass, 2 tbsp salt in the second glass and nothing in the third.

3:  Gently place an egg in each cup and see how the buoyancy is different in each because the density of the water is different in each cup!

**Spoiler alert** The egg should sink in just water – least dense liquid.  Next, the egg should float in 4tbsp salt as it is most dense and more dense than the egg.  Finally, the egg should half float/half sink about halfway down in the 2tbsp cup.  If the 2tbsp one sinks add more salt.  If it floats too high, add some plain water.



Enjoy a happy moment,

❤ Sara

More fun activities for little kids:

How to Make Giant Building Blocks: Big DIY Fun

Ice Cream Preschool Alphabet Games & Number Games

Easy Space Crafts: Three Out of this World Ideas

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