The lungs are like giant sponges which absorb oxygen from inhaled air and passes it around the body.  Unfortunately for smokers, the lungs also absorb the brown, gooey cancer-causing toxic tar from tobacco smoke.  This model demonstrates how a sponge lung can easily soak up a large amount of tarry substance.   You can squeeze out the ‘tar’ from the lungs and show that even if you squeeze out the ‘lung’ you cannot remove it all.  Give the message that you can’t squeeze out your lungs so its better not to smoke as you only keep topping up the tar levels.  Comes with latex gloves for use with the washable ‘tar’.  The tar and sponge can be bought separately.