Teaching Resources

Anna Pavan

Istituto Comprensivo Savona IV - Savona

associated teacher

Density (from PhET site)

Density.
The concept of density related to mass and volume.
Volume calculation by liquid displacement.
Identification of an unknown material by calculating its density.

The link between scientific experience and everyday life.
The parameters allowing the measurement of the density of a material can be learnt even by means of practical experiments performed with objects and materials which are easily available and of everyday use (balance, water, etc.).

Java is needed to visualize simulation

Comprehensive Institute Savona IV-Legino. Lower secondary school, first year (11-12 years), 18 students.

- At first the general concept of density was presented as property of objects related to mass and volume. As a first evidence, objects with similar volume but different weight were examined, as well as objects with similar weight but different volume.
- Then using the whiteboard (no computer lab was available), the teacher showed the resource to pupils in order to connect density to the phenomenon of floating and sinking of different materials.
- Thereafter, the resource was used by experiencing the proposed different variables: students, in turns, decided what to change and discussed the results with the rest of the class.
- The teacher asked students to plan a simple experiment with the purpose of reproducing at least partially what outlined in the on-line resource.
- The experiment planned was carried out after bringing from home simple materials. Students calculated density using a balance and the displacement of water when dropping an object. They also tried to identify unknown materials by calculating their density.
- Finally students, divided in groups, summarized the performed work and drew their conclusions writing a brief report.
- A short summary of the reports was produced as PPT presentation with the whiteboard and with the collaboration of the whole class (supporting info).

They did not find difficulties in understanding the contents and using the information to organize the practical activities.
They showed cooperative attitudes and managed to plan a simple practical activity on the basis of information got from the simulation .

The resource provided interesting insights to undertake, with the lab approach, a path of observation ad reflection on a material feature (density). In particular, it helps to develop the following skills:
- Measure the volume of an object by observing the amount of fluid it displaces or can displace.
- Provide evidence and reasoning on how objects of similar mass can have differing volume and on hon objects of similar volume can have differing mass.
- Identify the unknown materials by and reference tables provided in the simulation.

33_Report of the work made by the students.pdf