A01 Air can be compressed and expanded
....A02 Under reduced air pressure water boils at a lower temperature
A03 Respiration is a chemical reaction of air
A04 Earth worms and plants also need respiration
A05 Respiration of mosquitos needs air even in a water butt
A06 Yeast can thrive in Cola without air, producing big quantities of carbon dioxide
A07Green plants recycle consumed air
A08 Pure oxygen made from hydrogen peroxide (Teacher experiment)
.A09 Combustion in air and in pure oxygen (Teacher experiment)
A10 Steel wool (iron) changes its mass during combustion
A11 Air is consumed during rusting
A12 Steel wool changes its mass during rusting
A13 Cola can rust in a different way
A13a Rust protection by zinc coating
A13b Rust protection by tin coating
A13c Rust protection by plastic coating
A14   Zinc/air "battery": Electricity for a hearing aid