It makes no sense to be weaving with yarn and then to insert a piece of barbed wire. Sometimes integrating every subject in every unit simply does not fit. As the child sucks paint into the straw, places his finger over the end of the straw, and then releases his finger and slings paint on the paper, he is using the principle of air pressure he has just learned. This art activity reinforces the main theme of the unit. Let's face it.
Some units are heavy on science or history while other units are heavy on art or music.
Many moms are frustrated, when they cannot have 30 minutes of each subject balanced perfectly in each unit. This attitude causes the natural flow of a unit to be lost. All knowledge should further our understanding of God as well as equip us to operate in the world. Units on simple machines, inventions, and the Industrial Revolution, should emphasize the common character traits of the inventors such as resourcefulness and persistence. Children should focus on the character traits of those they study.