Ioan and Finn hunted round the house to find some items that they wanted to test. They were trying to work out which floated and which sank.


  • Bucket of water
  • Hula hoops
  • Household objects


Making predictions

Having previously used hula hoops to classify animals and sort magnetic eggs from non magnetic eggs, Ioan wanted to use the hoops to classify their predictions, of which items would float and which would sink.


Once they had made their predictions, it was time to test them. They started off with the hoop of objects they expected to sink. They added another hoop, to record any items that floated unexpectedly.

Next, they tested the objects that they thought were going to float. Again there was space in another hoop, to record any objects that sank.

Why do objects sink or float?

An object floats when the weight force on the object is balanced by the upward push of the water on the object. The upwards push of the water increases with the volume of the object that is under water; it is not affected by the depth of the water or the amount of water.

If the weight force down is larger than the upward push of the water on the object then the object will sink. If the reverse is true then the object will rise.

Rising is the opposite of sinking.

DfES Outcomes for EYFS and National Curriculum (2013)

Science Year 1 programme of study

Everyday Materials

  • distinguish between an object and the material from which it is made
  • identify and name a variety of everyday materials, including wood, plastic, glass, metal, water, and rock
  • describe the simple physical properties of a variety of everyday materials
  • compare and group together a variety of everyday materials on the basis of their simple physical properties.