Shoulders Bag backpack Significance was American gold rush, when the first batch of immigrants set foot on the mainland United States, they can be said to be poor and white, they had to work hard. Strong workforce makes clothes easy to wear, but also wear-resistant package Design Development backpack ago are H shape, the carrying of the system only depend on a solid frame backpack straps easily cause shaking, encountered intense exercise is not easy to protect the balance, after the invention of the package with shoulder strap belts and chest belt, combined with those who bear and backpacks and distributed to bear weight, the majority outside the frame backpacks have many small items Leans the bag provide placement Analysis Although there are many small items placed Leans the bag provided, but a solid outer skeleton frame backpack load center of gravity is usually higher than the shoulders and waist, so its weight to bear those who caused the center to maintain a balanced and forward lean, while outside the rigid backpack frame skeleton would reduce the rotation of the space between the road and a higher center of gravity caused by the process of difficult road to maintain a balance. Case Study Westward Movement Westward Movement History The first was dominated by agriculture during the initial development. Second, an industrial-based integrated development period. Three high-tech-oriented depth to the development period Background southern slaveholders and northern land speculators and poor people, want to acquire land in the west. Immigrants make the United States be able to carry out large-scale agricultural production, in order to be able to immense strength and size of the development of its rich industrial resources. The United States Government's land policy, transcontinental railway building and accelerate the development of the western. PROFILE of the Westward Movement on American economic, political and community have had a significant and far-reaching impact. Westward Movement completely changed the face of the United States, large areas of wasteland has been reclaimed from a large number of capitalist farms established, the development of agriculture in the western region for industrial development to provide a large amount of food, raw materials, exports and domestic market stimulated the Westward Movement American creativity and economic vitality of the United States enhance the comprehensive national strength and international status of the United States took off the entire national economy is of great significance.