Bash script to convert a string with space delimited tokens to an array

I have a string

echo $STRING

which gives

first second third fourth fifth

basically a list separated spaces.

how do i take that string and make it an array so that

array[0] = first
array[1] = second

etc..

I have tried

IFS=' ' read -a list <<< $STRING

but then when i do an

echo ${list[@]}

it only prints out "first" and nothing else