The heart is tasked with pumping blood throughout our body by rhythmically contracting its muscles. The human heart has 72 beats per minute and will beat over 2.5 billion times during an average lifetime.
There are two ways to go about making a heart costume, either an anatomically correct one or the more stylized-looking heart associated with Valentine's Day.
Being a children's play, going with the stylized look would be best. It would be less expensive and complex to make as well as being kid appropriate.
The spleen is an organ that is part of the body's lymphatic system and helps protect the body by clearing old blood cells and other foreign materials from the bloodstream, and it fights off any present infection in the body. If an infection develops, the spleen contains white blood cells called macrophages and lymphocytes that can destroy bacteria and dead tissue.
The spleen would be an easy costume to make using some foam and fabric as the organ looks like a maroon-colored lima bean.
Another costume idea would be the bladder. Party of the urinary system, the bladder stores and releases the body's urine. The bladder is a hollow, balloon-shaped organ. The bladder collects urine from the kidneys and releases it through the urethra when it is full.
A costume of the bladder would be in the shape of a large ball. To show the bladder being emptied and filled, the costume could be made out of a light fabric with the actor wearing a fan underneath. Turning the fan on would help expand the costume and show that the bladder is full. Turning the fan off will contract that costume and show that the bladder is empty.
While not necessarily an organ, another good costume idea would be the colon. The colon, shaped like a lower case "N," is located within the abdominal cavity and is an important part of the human digestive system. It's a hollow tube that is about 2 to 3 inches in diameter and approximately 5 feet long.
Since the colon is a giant, curved tube, creating a costume might be difficult. One way is to have a student wear all black clothing with a model of a colon attached. The black clothing would help draw attention to the colon rather than to the student.