For a number of years I have used model trains, cars, dollhouse furniture, figurines, and any other scaled replicas I could find to teach ratio and proportion.
Students begin by measuring real cars and furniture.
We also measure furniture at school and at home. Understanding of ratio and proportion begins when students measure models and scale them to the real life objects. Dollhouse furniture is scaled one inch to one foot. The simplicity of this scale makes the furniture ideal for a first look at scale replications. Students are given the opportunity to work with ratio without worrying about conversions.