If you don't find what you need on our site, please contact us so we can assist you. Starbucks Online Store Customer Service Team. Customer Service Team hours are Monday through Friday, 5:30 a.m. - 5:00 p.m. PT, Saturday, 7:00am - 3:30pm PT, Sunday, closed. Call us toll-free at 1-877-421-9062. Contact the Starbucks Online Store Customer Service Team via e-mail using the form below:
The smallest particle visible to the naked eye is 40 microns. To give you some perspective, a piece of hair's width can range from 40 to 120 microns.
From head to tail, human sperm cells measure about 50 micrometers (0.05 millimeter, or roughly 0.002 inch). The tiniest object you can see with your unaided eyes is about 0.1 mm--so forget about seeing sperm without a microscope. A human egg is about 30 times bigger--large enough to be seen with the naked eye.