EXPERIMENT: HEART RATE In this investigation, you will take your own pulse and a friend's to measure the rate of the beating of your hearts. Then, you will see what happens to your heart rates after strenuous exercise. Two methods are frequently used to check heart rate. The first method requires counting the number of heart beats in 15 seconds and then multiplying that number by 4. The second method requires counting the number of beats in 60 seconds. The abbreviated method of pulse-taking can be slightly less accurate than counting the number of beats in 60 seconds, but it is commonly used by people in the field of medicine to save time. You will take your own pulse using both methods and determine how accurate each method is. Here are your goals for this lesson: Calculate heart rate using both abbreviated and standard methods Compare a resting heart rate to a rate following brief exercise Record data and summarize findings This item is needed: watch with a second hand Follow these steps. 1. Hold the first two fingers of your right hand lightly against the inside of your left wrist. Another good place to find a pulse is on your neck, to one side of the voice box. 2. Feel the soft beat beneath your fingers. 3. Use the watch with a second hand to count the number of beats in one minute. Record the number of beats per minute. 4. Using the watch with the second hand, count the number of beats in fifteen seconds. Multiply your result times 4 for the number of beats per minute. Record. 5. Count the number of beats in ten seconds. Multiply your result times six for the number of beats per minute and record. 6. Take the pulse of one of your parents or friends. Record the number of beats per minute using the minute method, the fifteen second method, and the ten second method. Record the results. 7. Run in place with your friend for one minute. 8. Take both of your pulses again. Record them. Write a short scientific summary comprising 150 words of your findings from this investigation. Be sure to answer the questions below as well as including your own data and reflections. How many times did your heart beat in one minute when you took your own pulse? How many times did your friend or parent's heart beat in one minute? If you took the pulse of someone who was a different size or age than you, did you notice a difference in heart rates? Body size, age, and fitness level are factors in heart rate. Why is this? When you counted heartbeats over periods of ten, fifteen, and sixty seconds, did you notice differences in the final heart rates? If so, was the difference significant? Why is the ten or fifteen second method of taking a pulse less accurate than counting the beats in an entire minute? After you ran in place, what happened to your heart rates? Why do you think this took place? What did you find out from this experiment? Be thoughtful in your answer.