How to pass array to bash shell script?

How do I pass an array as a variable from a first bash shell script to a second script.

first.sh

#!/bin/bash
AR=('foo' 'bar' 'baz' 'bat')
sh second.sh "$AR" # foo
sh second.sh "${AR[@]}" # foo

second.sh

#!/bin/bash
ARR=$1
echo ${ARR[@]}

In both cases, the result is foo. But the result I want is:

foo
bar
baz
bat

What am I doing wrong and how do I fix it?