How do we create a vacuum?

How we create a vacuum depends on scale and purpose, from simple household suction to industrial high vacuum chambers. A vacuum is created by removing gas molecules from a sealed space to lower pressure below atmospheric pressure. Simplest way to create vacuum is using a vacuum pump that extracts air, such as piston pump, diaphragm pump, rotary vane pump for low vacuum, and turbomolecular pump or diffusion pump for high vacuum. For household vacuum cleaner, motor drives fan that expels air, creating low pressure inside that sucks outside air and dust in. For laboratory, you create vacuum by sealing container and pumping out air with vacuum pump, measuring pressure with gauge. For vacuum packaging food, you place food in bag and use sealing machine that sucks air out before sealing. For DIY demonstration, you can create partial vacuum by heating air inside jar and sealing it as it cools, or using syringe to pull plunger while tip sealed. For ultra-high vacuum for semiconductors, you need multiple stages of pumps, baking chamber to remove moisture, and leak-free seals. So creating vacuum requires enclosed volume, pump to remove gas, and pressure monitoring.