A transparent 10 cm cube with four coloured inserts and a 1 × 1 cm grid that demonstrates units of volume and the volume of a rectangular parallelepiped.
The unit volume model is intended for demonstration in mathematics lessons. It shows the concept of volume, the units in which volume is measured and the way the volume of a rectangular parallelepiped is found, and it lets the class work through exercises on converting units of volume and solve problems with geometric visualisation to hand. The model suits demonstration to the whole class as well as individual work by a student at the desk.
The base of the model is a transparent container in the form of a cube with an edge of 100 mm, made of non-brittle plastic, with a measuring scale applied to its side faces. A 1 × 1 cm grid is applied to the faces of the assembled cube: the grid is on the surfaces of the insert elements that form the faces of the model and is seen through the transparent walls of the container. Four insert elements of different size and colour are placed inside the container one after another: a white block 100 × 100 × 90 mm, a yellow block 100 × 90 × 10 mm, a yellow bar 90 × 10 × 10 mm and a small red cube 10 × 10 × 10 mm. Put together, all four elements fill the container completely, without gaps or overlaps, so the model shows which parts make up a volume of 1000 cubic centimetres, that is 1 litre, and lets the class follow the step from it down to a single cubic centimetre. Every element is taken out of the container separately for demonstration and comparison.
The separable part for demonstration measures 10 × 1 × 1 cm: the yellow bar together with the single red cube forms a row of 10 unit cubes, and the red cube of 1 × 1 × 1 cm separates from that row on its own. The larger elements separate in the same way, so the class can move from the whole 10 cm cube to a layer, to a row of ten unit cubes and to one unit cube of 1 cubic centimetre. The set includes the transparent container 100 × 100 × 100 mm, the white block 100 × 100 × 90 mm, the yellow block 100 × 90 × 10 mm, the yellow bar 90 × 10 × 10 mm, the red unit cube 10 × 10 × 10 mm, a passport with a warranty card and individual transport packaging. The model is supplied assembled, with all four elements inside the container, and needs no further assembly; the elements are also stored inside the container.
In a lesson the teacher shows the assembled container and explains that its volume is 1000 cubic centimetres, takes out the small red cube as the unit measure of 1 cubic centimetre, then removes the remaining elements one by one and counts by the grid on their surface how many unit cubes each of them holds, which together give the same 1000 cubic centimetres. On this basis the class writes down the relation 1 dm³ = 1000 cm³ = 1 litre, calculates the volume of an element as the product of its length, width and height and checks the result by counting the grid squares, and solves problems on converting units of volume and on ordering the elements by increasing or decreasing volume. The construction is designed for daily assembly and disassembly of the elements during lessons.
The model needs no power supply and works indoors in an educational institution at +5 to +40 °C and relative humidity of 40 to 60 % without condensation. The small red cube is a small part that can reach a child’s airways, so the model is not left unattended in the presence of children under three years. The container and the elements are wiped with a dry soft microfibre cloth, or with a cloth slightly moistened in water with a neutral detergent and then dried at once; solvents, alcohol, acetone and abrasives scratch and cloud the transparent surfaces. The container is protected from falls, impacts, heating and long exposure to direct sunlight. Marking and operating documentation are in Ukrainian, the packaging is an individual corrugated cardboard box with content fixing, the service life is 5 years and the warranty period is 12 months.
