The Life Cycle of Stars: The Hertzsprung-Russell Diagram

How to illustrate the life cycle of stars using a HertzsprungRussell diagram, a large sheet, and some students.

Apparatus and Materials

• Large white sheet
• Felt pens to colour in the sheet
• Facts cards about stars
• Weights to hold down the sheet

Health & Safety and Technical Notes

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Teaching Notes

• The life cycle of a star can be a fairly dry subject, as there is no easy way to simulate it on the Earth. This interactive exercise allows students to think carefully about where a star might be on a Hertzsprung-Russell (H-R) diagram at different times of its life.
• By using a large sheet to make a H-R diagram, it is possible to create an interactive exercise that students can get physically involved with.
• Although the H-R diagram is quite an advanced idea for some students, it can be relatively easily explained as a diagram that shows the relationship between the temperature and luminosity (brightness) of a star. This allows for a number of activities to be carried out.
• As students walk on the H-R diagram, they are demonstrating an understanding of how a starʼs properties change throughout its life cycle. The use of fact cards allows one student to call out a pair of values relating to a star, while another student (or a group of students) decides where they should stand on the digram to represent that part of a stars life.
• The fact cards can either be in the right order so that students can clearly see how a starʼs life is mapped out, or they can be mixed up so that they first have to be sorted in to the right order.
• Allowing students to produce the diagram that they will use for this activity, or for another group who will do the activity, will also help them understand what happens to a star during its life cycle.