Description How many breaths does it take to fill up an 2.4 m (8″) long plastic tube? The answer may suprise you & your students!. If you place it firmly to your mouth (like a balloon), it will take many breaths to blow it up. But if you hold it out in front of your mouth and blow, air pressure in the stream you produce is reduced, entrapping surrounding air to join in, filling up the bag. You can blow it up with a single breath! This is especially effective after your students have counted many of their own breaths in attempts to fill up the bag! • Comes with a Teacher’s Guide • Sold in a pack of 4 • Green
