The white scallop meat sold for cooking is an adductor muscle: it draws the animal's two shells together. Opening a whole scallop means releasing that muscle, separating it from the surrounding tissues, and keeping the edible meat clean and cold. Good sourcing matters just as much as neat knife work.
Begin with a suitable product
Buy shellfish from a reputable supplier with the appropriate identification or labeling. If you harvest your own, follow current local closures and harvesting guidance. Cleaning or cooking cannot be relied on to make shellfish from a prohibited area safe.
Ask a fishmonger to demonstrate the preparation for the species you have. Large sea scallops and smaller bay scallops differ in size and handling. The steps below describe the basic bay-scallop method taught by University of Florida IFAS Extension, keeping the white muscle only.
Open the shell without rushing
Prepare a clean work area, a bowl for the meat, a separate waste container, and a suitable blunt utensil such as a spoon or butter knife. Protect the hand holding the shell and keep it out of the utensil's path. If the shell resists, reposition it rather than forcing a sharp blade toward your hand.
For a bay scallop, hold the darker shell uppermost. Ease the utensil between the shells and detach the white muscle from the upper shell. Lift that shell away. Separate the other soft tissues from the white muscle, then release the muscle from the lower shell and transfer it to the clean container.
Keep discarded tissue and its liquid away from the finished meat. Inspect the muscle for shell fragments and remaining unwanted tissue. Rinse away grit with cool, clean water. If you cannot identify the parts confidently, stop and ask an experienced fishmonger rather than guessing what to retain.
Keep cleaning separate from safety assurance
Seafish's processing guidance explains why careful removal of viscera and avoidance of contamination matter. It also treats sourcing, testing, and controlled processing as parts of safety. A brief household rinse is not a test for marine toxins or a substitute for those controls.
Chill promptly and cook thoroughly
FDA advice is to refrigerate seafood at 40°F (about 4°C) or colder and use it within two days, or freeze it. Wash hands, tools, and surfaces after raw seafood handling, and keep ready-to-eat foods separate.
Cook scallops to an internal temperature of 145°F (about 63°C); the flesh should become firm and opaque. Keep the time out of refrigeration short. For a classroom observation, let an adult handle the shell and utensils, and keep specimens used for non-food experiments out of the meal.
Sources and further reading
UF/IFAS Extension: How to Clean a Scallop
FDA: Selecting and Serving Fresh and Frozen Seafood Safely
Seafish: Scallop Handling and Shucking Practices
Canadian Food Inspection Agency: Marine Biotoxins in Bivalve Shellfish