A small scale gas preparation kit for producing gases which can be collected over water, e.g. oxygen, hydrogen and carbon dioxide. The kit comprises of:-. Plastic tank with lid. Test tube stand. Five test tubes: 150mm x 24mm with stoppers. Thistle funnel. Test tube with side arm and one-hole stopper. Special glass chimney shelf. Delivery tube and tubing connector. It is not recommended that these tubes be exposed to temperatures above 60°C. The tank and lid form a storage box for all components.