Tuesday, 7 January 2014

Understanding the World: Science

Sink or Float

The easiest science lesson to do with little children is the sink or float lesson. It’s a very visual lesson and once completed, you can leave the water play out for the children to experiment for themselves.

It opens a discussion about suitable materials for boats, children can make predictions and easily see the results of their predictions.

I have done this lesson with children as young as 2 years old. They enjoy the instant nature of the experiments and are able to see which objects sink or float instantly.

sink or float

picture from myteacherpages.com

I wouldn’t expect children to be writing anything down about this experiment. When I do this experiment, I write a lot of notes about what they children have said, or video their predictions, and take photos of their independent play.

I would use as large a tub as you have in your classroom but it is essential that the sub is see-through. I usually empty a toy box and fill that with water.

sink or float tub

I made a Smartboard activity where you could either s0fplace the children’s predictions and tick or cross if correct or wrong, or where you can record the results of the experiment.

Page two of the Smartboard has a possible plenary activity or a starter activity you could use as a discussion point.

sof The sink or float lesson plan is available here.

This plan links to Communication skills as much as it does to understanding the world.

I try to always incorporate ICT into my lessons and I have found some interactive games for the laptops you could use or to have on your interactive whiteboard.

sof game 2 This is a good game for looking at sinking or floating!

It’s a very simple program with lots of clicking and talking so easy for even the little children to follow.
sof game A really lovely game for children exploring the sink or float experiment.

The part I love about this game is if you don’t put the water in the sink, all the objects fall to the bottom, so that if you fill the sink with water, the floating objects then float! A lovely little touch!

If you must do a worksheet for this activity, there are a number available. I like this one from JenMarzolo.com.


Kids Activity Blog has a nice worksheet as well as Kiwi Crate.com. Personally, I think the best website is having the children draw their own worksheets. I have included what I would make as a worksheet.

Sink or Float Worksheet

This worksheet has space for writing comments the children have made, a photo of the children playing in the water and space for the child to draw the experiment independently. At the bottom of the worksheet, I have a large space for the child to write their own name (a writing target!) and the learning objectives from the planning which links directly to the Early Learning Goals. You could also ask the children to label their diagrams.

Although, with photographs, independent drawing and Magic Moment cards, you don’t really need to use a worksheet.

I hope this has been useful! Please leave a comment!


  1. I found this very helpful. I am fairly new to early years(nursery 3-4 year olds). I find the children fascinating and fun to be with but I do struggle to think of activities that are going to be at the right level and engaging and also address a range of learning objectives - so this is very useful. thanks so much.