This is a Responsive Interpolation mixin for SASS! I built it while building my Poet CSS library http://yamartino.github.io/Poet. Simple give it an element like "h1", then set the size you want that text to be on a large screen, and on a small screen, and it will handle interpolating between the two making a smooth resizing of the text.

_interpolate.scss

// Responsive interpolation mixin, great for making resposive text, but can work on anything.
@mixin interpolate($elements, $min-size, $max-size, $precision: 10, $property: 'font-size', $unit: 'rem', $min-width: 360, $max-width: 960){
  $increment: ($max-size - $min-size)/$precision;
  @for $i from $precision through 0{
    @if $i == $precision{
      #{$elements}{
        #{$property}: #{$max-size - $i * $increment}#{$unit};
      }
    } @else {
      @media only screen and (min-width: #{$max-width - $i * ($max-width - $min-width)/$precision}px) {
        #{$elements}{
          #{$property}: #{$max-size - $i * $increment}#{$unit};
        }
      }
    }
  }
}