Smallest Thing
From atoms to quarks: how deep does the rabbit hole go?
In the beginning...
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Lessons
Powers of ten
Practice: Powers of ten
Scientific notation
Practice: Scientific notation
Milli, micro, nano
Practice: Match the sizes
Cells, bacteria and viruses
How many atoms fit across a cell?
Practice: Order by size
Practice: How many fit across?
Seeing the very small
Why light can't show an atom
Practice: Pick the tool
Inside an atom
An atom is mostly empty
Practice: Picture the empty atom
Inside the nucleus
Practice: What is it made of?
Do quarks have a size?
The Planck length
Practice: True or false
Practice: Place them on the ladder
Course Complete
Up next
How small can things get?
Zoom in through the scales of matter. Start from everyday objects and go deeper through cells, molecules, atoms, nuclei, quarks, and the limits of what we can measure.
Launch Lesson