Making a model of the heart pumping blood can be achieved by squeezing a ventricle of the model while simultaneously pitching the straw connected to it; this mimics the blood flow from the chambers to the body.
While the video excerpt offers a brief glimpse, here's a more detailed, step-by-step process involved in constructing a functional model demonstrating blood flow:
- Gather Materials: You will need items to create the chambers, valves, and vessels. Common materials include:
- Plastic bottles or containers (different sizes to represent atria and ventricles)
- Flexible tubing or straws (to act as arteries and veins)
- One-way valves (can be purchased or constructed using small flaps of rubber/plastic)
- Food coloring (to simulate blood)
- Water (to act as the "blood")
- A squeeze bulb or syringe (to manually pump the fluid)
- Scissors, glue, and other crafting tools.
- Construct the Chambers: Shape the plastic bottles or containers into the four chambers of the heart: the left atrium, right atrium, left ventricle, and right ventricle. Ensure each chamber is securely sealed.
- Implement the Valves: The valves are crucial for directing flow. You can purchase small one-way valves from a science supply store. Alternatively, create simple flap valves using thin rubber or plastic sheets. Place the valves between the atria and ventricles (mitral and tricuspid valves) and at the exit of each ventricle (aortic and pulmonary valves). These valves only allow fluid to flow in one direction.
- Connect Tubing/Vessels: Attach tubing or straws to the ventricles to represent the aorta (from the left ventricle) and the pulmonary artery (from the right ventricle). Also, connect tubing to the atria to represent the superior and inferior vena cava (to the right atrium) and the pulmonary veins (to the left atrium).
- Fill with "Blood": Mix water with food coloring to create a blood-like fluid. Fill the chambers and tubing with this colored water.
- Simulate Pumping Action: Use a squeeze bulb or syringe connected to one or both ventricles. Gently squeeze the bulb or syringe to simulate the contraction of the ventricle(s). Observe how the fluid is pushed through the valves and into the attached tubing. The pitching of the straw, as the video suggests, is essentially directing the flow while the ventricle is squeezed.
- Observe and Refine: Observe the flow of the colored water through the model. Ensure the valves are working correctly, preventing backflow. Adjust the tubing and connections as needed to optimize the pumping action.
Key Considerations:
- Valve Function: The success of the model depends heavily on the proper function of the valves. Ensure they are correctly oriented and allow fluid to flow in only one direction.
- Sealing: All connections between chambers and tubing must be airtight to prevent leaks and maintain pressure.
- Simplification: This is a simplified model. The real heart's pumping mechanism is far more complex, involving coordinated electrical signals and intricate muscle contractions.
This project provides a visual and hands-on way to understand the basic principles of heart function and blood circulation.
