Begin the class with a discussion of the human heart. Students should brainstorm what they already know about their own hearts. Students may discuss:
- the location of the heart
- the function of the heart
- how exercise affects the heart
Distribute a copy of the How Big is Your Heart? activity sheet to each student.
This activity sheet focuses on the relative size of the heart; in particular, the dimensions of the fist are related to those of the heart. Making predictions and models is an integral component of this lesson.
Read the introductory information to the students and give each student (or group of students) a ruler and a piece of string approximately 40 cm long.
Have the students measure the length and width of their fists. (Students may need to help each other measure.)
Then, ask them to wrap the string around their fist, including their thumb, and measure that distance with their ruler. Some students may ask what to do, since the thumb may protrude as they make their fist. Note that students should use the same unit of measurement, centimeters or inches, throughout the entire activity. Whichever unit they choose to use will depend upon their knowledge of and experience with that unit.
Based on their fist's length, have the students estimate the length of their heart.
Next, have the students determine the distance around the fist of a teacher, an older friend, and a parent. Allow them to predict whose heart they think is biggest, given the fist measurements.
Have the students predict how long and wide their heart will be when they are sixteen years old.
Finally, have students use construction paper to make a model of their heart, using their fist as a guideline. Have the students record the length, width, and distance around their model.
