If you had a 5-litre and a 3-litre bowl and access to water. How would you measure exactly 4 litres?

Fill the 5-litre bowl and overspill water to the 3-litre bowl, which you empty afterwards.
From the 5-litre bowl overspill the 2 remaining litres to the 3-litre bowl. Refill the 5- litre bowl and fill in the 3-litre bowl (with 1 litre), so there stay the 4 required litres in
the 5-litre bowl.