Ghost Heart

Changing heart rate

Duration: 40 minutes

Resources:

• Stopwatch
• Planning an investigation activity sheet
• Observation recording table
• Exercise equipment, e.g. jump rope, soccer ball (optional)

Key Learning:

This investigation asks the students to explore how different exercises affect heart rate. It encourages them to think about how hard their heart has to work to pump blood around the body. The investigation involves important scientific skills, including mathematical calculations and accurate timekeeping.

Activity instructions:

1. Divide the class into groups of four and distribute the resources. Explain to the class that they are going to carry out an investigation into the effects of exercise on heart rate. Safety note: Ensure that the chosen exercise activities are appropriate for both the space and the students’ clothing/footwear, and be aware of any physical or health conditions that may affect or limit participation, such as asthma.
2. Ask the groups to plan their investigations using the Planning an investigation activity sheet. Note: Example exercises include jogging on the spot, star jumps, skipping, push-ups and sit-ups.
3. Ask the groups to predict which exercise will increase the pulse rate the most and why. You may want to use the following prompt questions:
   
   • How many parts of your body are actively engaged in each exercise?
   • Why do you think your heart needs to work harder in some exercises compared to others?
4. Ask the students to assign each member of the group a different responsibility: someone to do the exercises, someone to measure their pulse before and after, someone to time the exercises, and someone to record the results in the Observation recording table.
5. Show the groups how to measure resting heart rate by lightly pressing their fingers against the person’s wrist or neck, and counting the number of pulses in 15 seconds. They can then multiply this number by four to work out the number of beats per minute.
6. Allow the groups time to complete their investigations. They should measure the volunteer’s pulse rate before and after each of the three exercises, and record their results in the Observation recording table. Remind the students that the type of exercise is the only variable that should change during this investigation; all other variables, such as the person doing the exercise and the length of time they exercise for, should be kept the same.
7. Once the groups have gathered their results, ask them to complete the last section of the Planning an investigation activity sheet.
8. Discuss the results as a class. Were their predictions correct? What could they do differently next time? Did the person’s heart rate return to its resting rate between each exercise? If not, how might that have affected the results?
9. Ask the groups to write a short paragraph that interprets their results and draws a conclusion. They could also create a line graph or bar chart to display their results.