• Question: why is it that when humans jump into the air they are pulled back down to the ground by gravity but when birds fly they don't fall immediately , they are able to just soar in the air and continuously fly for quite a while , why is that?

    Asked by BronaghR17 to Chris, Sarah on 17 Nov 2017.
    • Photo: Chris Werner

      Chris Werner answered on 17 Nov 2017:

      Good question, other than a few differences such as air sacs connected to their lungs to make them lighter and a lightweight skeleton with hollow bones, birds can fly because their wingspan and wing muscle strength are in balance with their body size. Humans are useless in this regard, we are heavy, we can’t fly and we don’t have wings. If you look at the huge pterosaurs which roamed the skies during dinosaur times, some of them had bodies the size of a man with 12 metre wing spans, you may ask how did this fly? Same reason as above and weighed only a few tens of kilograms. Its all about the wing strength in comparison to body size, and also air resistance. If Earth had no atmosphere and was a vacuum, they’d fall at the same rate.

    • Photo: Sarah Guerin

      Sarah Guerin answered on 17 Nov 2017:

      Very interesting- the physics of flying is super complicated, but Chris is right it’s all about the wings, and how they interact with air and wind. Scientists still don’t know how bumblebees can fly- because their wings are small and their bodies are big it shouldn’t be possible mathematically. Nature seems to always find a way to make things happen, and we are always trying to understand Nature more.

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