Electrons through two slits, one at a time

Fire electrons one by one, watch fringes build up, then find out which slit they used.

Interactive

electrons0

wavelength λ0.727nm

fringe spacing1.45mm

Electron speed1 × 10⁶ m/s

Firing rate

Which-slit detectors

The math, with your numbers

\lambda = \frac{h}{m v} = \frac{6.63\times10^{-34}}{9.11\times10^{-31} \times 1\times10^{6}} = 0.727\ \text{nm}

\Delta y = \frac{\lambda L}{d} = \frac{0.727\times10^{-9} \times 1}{0.5\times10^{-6}} = 1.45\ \text{mm}

Slits 0.5 μm apart, each 0.12 μm wide, screen 1 m away. No single dot can be predicted; only the pattern can.

Try this

→Set it to One by one and watch the first 20 dots. Could you guess there would be stripes?
→Double the electrons' speed. What happens to the wavelength and the fringe spacing?
→Turn on the detectors and let a thousand electrons through. Where did the dark stripes go?

Want to know why it behaves like this?

The lesson “Matter Waves & the Uncertainty Principle” explains it step by step: If an electron is a particle, how can it go through both slits at once?

Read the lesson

Electrons through two slits, one at a time

Fire electrons one by one, watch fringes build up, then find out which slit they used.

Electrons through two slits, one at a time

Interactive

electrons0

wavelength λ0.727nm

fringe spacing1.45mm

Electron speed1 × 10⁶ m/s

Firing rate

Which-slit detectors

The math, with your numbers

\lambda = \frac{h}{m v} = \frac{6.63\times10^{-34}}{9.11\times10^{-31} \times 1\times10^{6}} = 0.727\ \text{nm}

\Delta y = \frac{\lambda L}{d} = \frac{0.727\times10^{-9} \times 1}{0.5\times10^{-6}} = 1.45\ \text{mm}

Slits 0.5 μm apart, each 0.12 μm wide, screen 1 m away. No single dot can be predicted; only the pattern can.

Try this

→Set it to One by one and watch the first 20 dots. Could you guess there would be stripes?
→Double the electrons' speed. What happens to the wavelength and the fringe spacing?
→Turn on the detectors and let a thousand electrons through. Where did the dark stripes go?

Want to know why it behaves like this?

The lesson “Matter Waves & the Uncertainty Principle” explains it step by step: If an electron is a particle, how can it go through both slits at once?

Read the lesson