A full differentiated lesson on the topic of breathing. The lesson is based on the Activate 1 book (B2.3) but can be used for others. The lesson includes video, a demonstration using a bell jar and a simple practical exercise where students observe an increase in CO2 in expired breath using lime water (can be done as a demo). Homework is also included or can be deployed as a stretch activity. PowerPoint animation and timers are included to promote pace and self/peer mediated correction of answers.