Åka means to ride a vehicle that you're not driving. Cars, trains, buses, airplanes and the like. But not bikes! Bikes have their own verb, att cykla.
Gå on the other hand was explained well by samulili above.
Wiktionary states that åka generally means to deliberately change ones location, as in to travel or go. Jag åker hem - I am going home Du åker till England - You are going to England Att åka tåg - To travel by train Vill du åka med - Do you want to come along
More importantly gå means to go by foot. So you would åka med bus and not gå med bus unless you are really strong. And you would not gå till Hawaii unless you are the second coming.
Buses themselves, however, can gå even though they don't have feet. But can snakes? I don't know, we need a native speaker to answer that.
Captain Native Swede to the rescue!
Snakes never gå, they kryper (infinitive krypa), meaning "crawl".
By the way, to ride the bus (or other vehicles) doesn't require med, we just say jag åker buss. :)
On "Kvinnan åker" - "The woman leaves" was a correct answer, why is "They leave" not accepted for "De åker"? Any reason for that or is this inconsistency taking place?
I found går and åker both are not introduced with 'leave' but sometimes later have that meaning in certain circumstances. Would love to have it consistent or at least explained in the mouse-over or tips :-)
That is what I wrote (I looked it up in a dictionary and it said 'travel' or 'drive' not 'go'
Yes. Travel = resa, åka, färdas. He travelled abroad: Han åkte/ reste utomlands. Light travels faster than sound: Ljuset färdas snabbare än ljudet. (not åka/resa).