Science in the Early Years - Sink or Float?

I have been planning to extend some of the Montessori cultural ideas into my setting for a while now and organised myself to do it last night!  The Montessori cultural curriculum has some lovely suggestions for science activities that early years children can learn from in a hands-on, child-led way, supporting their knowledge and understanding of the world, amongst other things.

To set up an activity for exploring objects that sink or float,  you need:

• A tray that will hold a glass bowl/vase (glass because you can see through it and observe the objects that have sunk); fill the bowl three quarters full of water. 
• Next to it you need a plastic tray, box or basket that holds eight small objects that vary in size and material. 
• Objects made from different materials; on the tray above I have a light plastic ball, a plastic dinosaur, a small pebble and a marble (inside the small copper pot on this picture), a cork, a piece of bark, a shell and a small copper pot.
• A cloth to dry the objects and their tray with afterwards.

You can also have a laminated piece of card or paper that has the words 'float' and 'sink' on it including a simple diagram of an object below the water line and on the waterline for non-readers.

I like to get the child to make a hypothesis about what will happen such as "Do you think the shell will float or sink?" - you could also ask why they think that, giving you an amazing insight into their reasoning and knowledge (see sustained shared thinking for more tips on asking questions open-ended questions!)

Some of the thinking that came out using this activity was:

• That the dinosaur looked bigger at the bottom of the water because the water reflects it.
• That the shell was nice and thin like the pot so it would float (it sank of course).
• If you drop the pot from a low height it would float but when you drop it from a high height it sinks because it fills with water and goes heavier then.

Not all of the thinking is scientifically accurate but the children are making close observations of the materials and what is happeneing and using creative thinking to apply that knowledge to the other objects.  By exploring this themselves and actually experiencing it, it has more value than being told or reading about it in a book.

Here there is an attempt to balance the dinosaur on the bark to make it float instead of sink. Good Thinking!!

To make this suitable for toddler/baby exploration, put the objects into a wide necked plastic bottle or tub and fill half full with water and screw the lid on tight.  Every way they turn this up, the floating objects wil float and the sinkers will sink!  Differentiation in a nutshell!!