# Science/Physics KS2/KS3: Helicopter rescue and the science of floating

Using the ‘real-life’ scenario of raising lost treasure from the bottom of a swimming pool children are set the challenge of using the science of ‘floating’ to solve the problem.

Children carry out an experiment to investigate the amount of air needed to float different weights, using cut-off drinks bottles filled with air to raise weights in water tanks.

They record their measurements and present them on a chart and then look for patterns in the results.

They identify the relationship between the mass of the object in grams and the volume of air in millilitres needed to float the object.

The concept of displacement, caused by the bottle pushing water out of the way, is explained by immersing a bottle in water, and feeling the forces acting on the bottle.

Floating happens when the force of the water pushing upwards equals the force due to gravity acting downwards.

Using the results from the experiment children are asked to predict how much air will be needed to float the treasure and then their prediction is tested out.

This short film is from the BBC series, Operation Awesome, in which students explore a range of amazing practical science challenges with presenter Steve Mould.

### Key Stage 2:

This short film could be used to effectively introduce the concept of floating.

It could also be used to illustrate water resistance and balanced forces.

You could use this as an illustration of using scientific method to solve problems and answer questions.

Pupils could explore the effect of buoyancy on the apparent weight of different objects that float and sink.

You could ask them to apply their understanding to explain why solid steel objects sink but boats made out of steel float.

### Key Stage 3:

This short film could be used as an introduction to the concept of balanced forces.

You could ask your pupils to draw force diagrams to name the forces acting on objects that float or sink, their relative sizes and the resultant force acting.

This could be used as an introduction to enable students to use experimentation, to be able to explain floating and sinking in terms of the relative densities of different materials.

### Curriculum Notes

This short film will be relevant for teaching science at Key Stage 2 or Second Level in Scotland, or physics at Key Stage 3 or Third Level in Scotland.