Pagination: Why does length and count return different values?

gistfile1.rb

# in spec/models/project_spec.rb

describe '#paginate' do
  before(:all) { 9.times { FactoryGirl.create(:project) } }
  after(:all)  { User.delete_all }

  it 'returns paginated values' do
    Project.paginate(page: 1).should eq Project.first 5
    Project.paginate(page: 1).length.should eq 5
    Project.paginate(page: 1).count.should eq 9
  end
end