experimental material; material for experiments
Refers to substances, specimens, or items used in scientific or technical experiments.
I ordered new experimental materials.
This experimental material needs to be kept refrigerated.
実験器具 refers to laboratory apparatus or equipment, while 実験材料 refers to the consumable materials or substances used in experiments.
試料 is a more formal term for a sample or specimen, often used in analytical or testing contexts, whereas 実験材料 is broader and can include any material for experimentation.
Compound of 実験 (experiment) and 材料 (material). The exact historical derivation is uncertain, but the meaning is transparent from its components.