Adafruit will not be shipping USPS orders Monday February 18, 2019 for the federal holiday, Presidents Day.
Expedited USPS orders placed after 11am ET Friday February 15 will go out Tuesday February 19.
It is impossible to overstate the importance of this accidental discovery. The work that Fermi subsequently led to exploit this revelation, culminating in the development of the first nuclear chain reaction on December 2, 1942 in Chicago, was based entirely on the “slow neutron” effect. The graphite bricks that formed the structure of the first atomic pile served as a moderator to slow down the neutrons emitted from the uranium slugs embedded throughout the pile, enhancing the probability of fission. Not only are all nuclear reactors based on this effect; it was an essential aspect of fission research that led, inexorably, to the development of nuclear weapons.
Stop breadboarding and soldering – start making immediately! Adafruit’s Circuit Playground is jam-packed with LEDs, sensors, buttons, alligator clip pads and more. Build projects with Circuit Playground in a few minutes with the drag-and-drop MakeCode programming site, learn computer science using the CS Discoveries class on code.org, jump into CircuitPython to learn Python and hardware together, or even use Arduino IDE. Circuit Playground Express is the newest and best Circuit Playground board, with support for MakeCode, CircuitPython, and Arduino. It has a powerful processor, 10 NeoPixels, mini speaker, InfraRed receive and transmit, two buttons, a switch, 14 alligator clip pads, and lots of sensors: capacitive touch, IR proximity, temperature, light, motion and sound. A whole wide world of electronics and coding is waiting for you, and it fits in the palm of your hand.