For this activity I use rolls of adding machine tape- you need something at least 460 + a little extra cm long. Students use a meter stick to mark off TODAY. Then, leaving the meter stick in 1 spot, they mark off each of the periods at the correct measurements.
Students then add in important events in geologic time onto the timelines.
The result is a LONG roll of geologic time! A great VISUAL to the hard to conceptualize geologic timeline.