Simplify the following text for a Grade 9 native English-speaking person.
Original: Though SI prefixes may also be used to form multiples of the second ( such as â kilosecondâ , or one thousand seconds ) , such units are rarely used in practice .
Simplified: Though SI prefixes may also be used to form multiples of the second such as kilosecond ( one thousand seconds ) , such units are rarely used in practice .