Worksheets and lesson ideas to challenge students aged 11 to 16 to think hard about homeostasis (GCSE and Key Stage 3)
Homeostasis is all about trying to keep internal conditions in the body constant. Students will be familiar with thermostats and heating systems and so this can be a great place to start. The concepts of negative and positive feedback are really useful here – what has gone wrong in the video below? What internal conditions are not being kept constant? And what is the role of positive feedback in making the guardsman collapse?
Where to start?
It’s important that students appreciate the concept of detecting change when learning about homeostasis. A fun way to introduce this idea is to challenge students to keep a beaker of water at 40 °C using only ice and a Bunsen burner. This should be done as a demo. Students can plot the temperature of the beaker every 20 seconds for 10 minutes. After the experiment ask students to comment on the difficulty of keeping conditions constant – ultimately this is about a delay in the response following detection of a change. Now relate this to temperature control in the body to explain why a human’s body temperature is never completely constant.
Understanding negative feedback
GCSE worksheet on homeostasis and internal conditions. Students identify which line on a graph best describes the change in room temperature over a five hour period. The idea behind this activity is to help students understand that internal conditions are not absolutely constant – they fluctuate around a narrow range called the set point. (PDF)
Comparing the hormonal and nervous systems
GCSE worksheet comparing the hormonal and nervous systems. Students are presented with two aliens. One alien has a nervous system and the other alien has a hormonal system. Students then think through how their lives and biology would be different. This is quite a challenging worksheet with lots of application but could be easily adapted for your class. (PDF)
- Compare and contrast the action of negative and positive feedback in organisms. Give examples.
- How does homeostasis facilitate optimum enzyme activity.
- Why might an organism not respond immediately to minor changes in the internal or external environment?
- Is temperature regulation in organisms always physiological?