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.
With the naked eye, the part between 400 and 700 nanometers called the visible spectrum. Red to Violet/Blue. Humans can NOT see ultraviolet light, only what is reflected off u â¦ sing something within the visible spectrum. Humans also can NOT see infrared light without special instruments.