Your student builds a four-chamber heart model using plastic bottles as atria and ventricles, plastic tubing as blood vessels, and drinking straws trimmed into one-way valves. Blue water represents deoxygenated blood in the right side, red water represents oxygenated blood in the left side, and squeezing each ventricle shows exactly how pumping pressure moves fluid through the pulmonary and systemic circuits. This lab sheet is well suited for grades 5 through 8 and works as a hands-on centerpiece for a human body or circulatory system unit.

Making a model heart pump this way gives your homeschooler a concrete look at a process that textbook diagrams alone rarely make click. The sheet walks through assembly in ten numbered steps, then asks five observation questions comparing the model to the real heart, including why the straw valves matter and what limits the model. A conclusion prompt asks students to propose improvements, which pushes the thinking past construction into genuine scientific evaluation.