Shirley Temple wears me on her head, Singapore slings me, and it sounds like Sundays aren't the same without me. What am I?

In the hands of a monkey I gum up the gears A simple design That’s lasted for years In heartbreak or sadness I’m felt in your gut Or, grip me tight to bust a nut

Spring from the earth, But return in a bit, Safety intention? To wit, lone armpit

Despite my size I'm a source of power I'm in a cell, but you need not cower! You might know of my skills supreme From a schoolbook or from a meme.

Don't eat this hue if snow If you do, you'll feel low A coward and the sun, Both share the same one!