The Science Teacher Guidelines state that 'Practical experiences that help children to become familiar with the terms 'pushing', 'pulling', 'floating' and 'sinking' would be a useful starting point for work on forces. (Teacher Guidelines, p. 107 ).
Some of the main approaches which the Science Teacher Guidelines note as central in the approaches to teaching science are encouraged in this unit on floating and sinking. Others can be more easily attended to in a science lesson where children can interact with peers and with each other as they engage in activities and discussions.
These approaches are ones which:
- Identify pupils' ideas: children can be asked to note why they think an object sinks or floats, if an object which is suspended in the water or has some part above the water should be classified as a floaters or a sinker. They can be asked to explain sinking or to draw diagrams to explain floating etc.
- Help pupils to articulate their ideas (through discussion, writing, drawing)
- Ask pupils questions that challenge their misunderstandings or misconceptions
- Encourage children to observe in detail and to reflect on what they have observed. As well as the on-line simulated investigations on floating and sinking children can also investigate real situations. Example- Try to press a large sheet of polystyrene on a large container of water. Children can comment on what they notice as they push down slowly ( a 'push up' force)
- Promote demonstrations that reinforce basic concepts
- Perform demonstrations that cause pupils to modify their ideas
- Train pupils to ask questions that might lead to an investigation
- Enable pupils to set up investigations - for example through investigations using small objects children may come to understand that whether an object floats or sinks in water depends on whether or not the object is as heavy as the amount of water that it has displaced when placed in the water.
'First hand investigation is central to the way in which young children learn science. It equips them with the realisation that they can provide their own answers to problems and that they can learn from their interaction with things around them.' (Teacher Guidelines, p. 2).
The role of the teacher in developing children's understanding in science is very important. To assist children to comprehend floating and sinking there are some key concepts about floating and sinking that will need to be understood. The readiness of children to understand some of these concepts will vary in third and fourth class and so the explanations and clarifications should be linked to the children's questions and to observations made during practical work.