Task 1: Density of metals

Topic: Metals

Level: Primary /1.–5. Graders/

Thematic Unit:

Subject: science

Recommended age of pupils: 6–11 years old or older

Time allocated: preparation: 10 minutes, implementation: 15 minutes


For each working group of between 2 to 4 pupils, the teacher prepares three objects made of various metals (aluminium, iron and copper), scales, graduated cylinder, a nail. The teacher chooses the size of the graduated cylinder according to the size of the objects so that they could be easily put in and taken out.

Pupils number the objects 1-3, describe their look (colour, sheen) and make a presumption of which metal the objects are made from and write that in the table. Next, pupils make an incision into each of the metals and write, in Table 1, which metal they made the deepest incision into (hardness 1), and which metal was the hardest to make the incision into (hardness 3). Pupils weight the objects on the scales and write the read values in the prepared Table 2.

Pupils fill the graduated cylinder with cold tap water and write the amount of water in the table. After that they put the first object into the graduated cylinder and read the new value of the water volume, they write the findings in Table 2. The amount of water in the graduated cylinder must cover the object entirely but at the same time the measuring range on the graduated cylinder must not be exceeded. Pupils pour out the water from the graduated cylinder and take out the first object. They continue doing the same task with the second and the third object. At the end, pupils calculate the density of an object – using Table 3 and in Physical and Mathematical tables, they look up which metal the density belongs to.