- dark energy, 1, 2, 3, 4, 5
- dark matter, 1, 2
- Darwin, Charles, 1, 2
- Davisson, Clinton, 1, 2
- decoherence, 1, 2
- Democritus, 1, 2
- deuterium, 1, 2
- dice rolling: predicting outcome, 1
- diffraction patterns, 1
- dimensions, extra, 1
- dimmer switches, 1
- Dirac, Paul, 1
- disc drives, 1
- DNA, 1
- doors: automatic opening, 1
- dynamos, 1
- Dyson, Freeman, 1