Falling down

Do you know seagulls? Most of them eat fish or shells. The way they open the shells is very interesting. They fly high in the air and drop the shells on a hard floor like a street or rocks. Once open, the shells are eaten quickly by the birds. You are probably wondering, why I talk about seagulls and shells while the title of the blogg says something about Physics. To get into the theme I will talk about, I first have to tell you a little story that will convince you that birds are masters of applied physics.....