Matter does not vanish when a leaf falls. Fungi and bacteria break down organic material. Earthworms help by eating and fragmenting litter; they are detritivores, not microbes. Plants take up mineral nutrients and water through roots, but most of their new dry mass comes from carbon dioxide, not soil. Safety: Do not handle soil organisms, mould or decay. Stop: Stop after tracing one complete path. Do not make a compost jar or collect rotting matter.

Materials: Paper; Pencil 1. Draw six boxes: soil mineral nutrients; oak; caterpillar; dead leaves and animal remains; earthworm; fungi and bacteria. Copy this model fact: some mineral matter from soil enters oak, then a caterpillar that eats its leaf. 2. Add arrows soil → oak → caterpillar → dead material. Add oak → dead material for fallen leaves. Add dead material → earthworm and dead material → fungi/bacteria. Label the worm route fragments and waste become material microbes can break down. 3. Add fungi/bacteria → soil mineral nutrients. Trace one imaginary unit of mineral matter through the oak and caterpillar and back to soil. Write that this is an illustrative path, not a measured particle journey. 4. Add air carbon dioxide → oak and water → oak. Draw sunlight → oak with a different arrow style. Explain why matter can cycle while energy passes through and spreads as heat rather than returning as usable sunlight. Done: Complete the labelled matter model, one traced mineral path and a separate energy-input arrow. Proof: Keep the model and explanation. Note adult help with detritivore, mineral or arrow labels. Stop: Stop after tracing one complete path. Do not make a compost jar or collect rotting matter.