Thermohaline means temperature-and-salinity related. At comparable pressure, colder or saltier seawater is generally denser. The AMOC carries warm upper water north and colder deeper water south in the Atlantic. Winds and mixing also matter. This model is not a single pipe followed by all water. Safety: No water, salt, glass containers, heat sources or weather exposure. Stop: Stop with the paper model. No saltwater, heating, cooling or density experiment is required.

Materials: Paper; Pencil 1. Draw tropical Atlantic on the left and northern Atlantic on the right. Draw a warm upper arrow northward, an arrow for heat leaving water to air, a cooling/sinking arrow in the north, and a cold deeper arrow southward. Label the loop a simplified AMOC model. 2. Compare three illustrative equal-volume cards at the same pressure: A warm salty water; B colder water with the same salinity; C water at B’s temperature but fresher. Mark B denser than A and B denser than C. Do not rank A against C without more data. 3. Add freshwater to the northern box on paper. Explain how reduced salinity could reduce density and make sinking harder, other factors equal. Write a conditional prediction: weaker northward heat transport could alter northern European climate relative to a world with stronger transport. Do not predict a collapse date or an instant ice age. 4. Add separate budget notes: oceans store about 90% of excess warming heat; a NOAA summary estimates uptake of about 25% of annual human-released CO2. These have different denominators. Explain that UK–Canada winter differences also involve prevailing winds and geography, not latitude or AMOC alone. Done: Complete the current loop, both supported density comparisons and one qualified weakening explanation. Proof: Keep the arrows and budget notes. Record adult help separating temperature, salinity and heat transport. Stop: Stop with the paper model. No saltwater, heating, cooling or density experiment is required.