The primary sector of the economy is the part of the economy that is involved in extractive work. This involves getting raw materials from nature. In the area of making potato chips, jobs in the primary sector would have to do with raising the potatoes. These would be jobs like running a potato planter, weeding the potatoes, or harvesting the potatoes.
The secondary sector of the economy is involved in manufacturing. This sector takes the raw materials extracted by the primary sector and makes them into things that people want to buy. Everyone who works at the potato chip factory would be involved in the secondary sector. These would be the people who run the machines that make the potatoes into potato chips.
The tertiary sector of the economy is the sector that performs basic service tasks. These tasks could include transporting the potato chips from the factory to the store where they are sold. The person who puts the potato chips on the shelves or other displays is also part of the tertiary sector. These people are not making any goods. Instead, they are performing services that are related to the selling of the potato chips.
The quaternary sector has to do with more complicated services. These are the jobs that require greater skill and more education. For example, a person who designs the machines that make the potato chips would be working in this sector. Another person in this sector would be a food scientist who researches ways to make tastier and healthier potato chips.