Bernoulli Bag, Helps explore Bernoulli's principle of air pressure, Pack of 4

Details

Place it firmly to mouth (like balloon), it takes many breaths to blow it upWhen held in front of mouth and blown, air pressure in stream produce is reducedEntraps surrounding air to join in filling up bag, hence can be blown in single breathEffective after students have counted many of their own breaths in attempting to fill up bag