Do the same to other pieces of pip of different lengths. Do the same with bottles. Use bottle of different sizes or add water to decrease the length of the column of air. Blow across the top of a narrow mouthed bottle to produce a tone. Again, try different size bottles, and add water to some to produce different tones.
Test tubes work quite well if some are available.
Flatten the end of a drinking straw, and cut the flattened end to a point to simulate a double reed such as an oboe. This takes a little practice. Paper straws work most easily. Plastic straws work fine but you must work harder to flatten the end. Cut straws to different lengths to get different pitches.