I got pupils into groups and got them to model lungs using straws, cocktail sticks and raisins. The fastest group to create the most accurate model! It worked really well! When explaining gas exchange in our bodies I got pupils to volunteer and gave them signs saying 'lungs&', &';heart', &'red blood cell&';, 'oxygen&' etc. and got them to act it out as I explained it! Hope you enjoy teaching it- I did :)!