This 1915 washing machine revolutionised clothes washing in the early 1900s. Up until then washing was done by hand, using a tin bucket (or a copper) and boiling water.
Washday was traditionally a Monday (based on the premise that if you did your washing on Monday it would be clean and dry by Sunday, the day of rest and clean clothes).
Washing was a labour intensive chore, and usually took all day.
You didn't have the luxury of changing the water, so you started with the least dirty clothes, and worked your way up to the dirtiest.
First the water needed to be carried from a pump and boiled. Then the clothes were plunged in the water, then scrubbed with soap against a washboard.