Science kits address the critical need in schools lacking laboratory…

Concept — Science at the primary stage is learnt by doing: a child builds a scientific idea by handling materials, observing what happens and inferring from it, rather than by being told the idea. A science kit is a portable, self-contained box of apparatus, specimens and consumables put together so that this doing can happen anywhere, independently of a fixed laboratory.

Application — The stem fixes the constraint: the school has no laboratory. A laboratory is permanent infrastructure - fixed benches, water and gas lines, power points and storage - and building it is exactly what such a school cannot do. The kit substitutes for that infrastructure, not for the teacher and not for the textbook: it places apparatus in the pupils' hands on an ordinary classroom desk. What the kit therefore restores is the single function the missing laboratory used to carry, namely the pupils themselves performing experiments. The practice it enables is hands-on experimentation without requiring permanent infrastructure.

Contrast with the other practices

• Group memorization of scientific terminology is a verbal-recall exercise; it runs on word lists alone, so no apparatus is needed to make it possible in the first place.

• Standardized testing with theoretical questions is an assessment carried out on paper; question papers and answer sheets, not apparatus, are what it depends on.

• Teacher-led lectures with textbook illustrations keep the child a listener and viewer; the textbook and the blackboard already support them in a school with no laboratory.

• Hands-on experimentation is the one practice of the four whose materials a kit actually supplies, which is why the absence of a laboratory removes this practice and a kit brings it back.

Cross-check — Read the requirement in the reverse direction: memorisation, written testing and lecturing each survive untouched in a school that has no laboratory, so none of them is the practice the missing laboratory took away. Only learner-performed experimentation is lost with the laboratory, and only it is restored by a kit - which is why NCERT-type science kits are supplied precisely to schools without laboratory facilities.