There are two holes in a coffee cup. Which one is for drinking?

Two holes in a coffee cup

Coffee cups are one of the most common containers in our daily life. They usually have two holes. So, what are these two holes? Let's explore.

Where is the drinking hole?

First, let's look at a hole on a coffee cup - the drinking hole. This hole is usually located near the mouth of the cup and is used for people to pour coffee or other beverages into their mouths. This design is very practical because it can easily control the speed and amount of liquid flowing out.

Where is the other hole?

In addition to the drinking hole, there is another small hole at the bottom or side of the coffee cup. This small hole is called an exhaust valve or atmosphere valve. It plays a role in balancing the internal and external pressures and preventing hot liquids from splashing out.

Exhaust circuit and thermal insulation effect

When you pour hot water into a coffee cup, a closed space is formed inside. As the water expands and produces steam due to the heating, the pressure inside will gradually increase without an exhaust circuit. At this time, if you try to drink the coffee, the hot liquid may splash out.

With the exhaust valve, the steam can be discharged from the cup through the small hole, thus balancing the pressure inside and outside the cup. In this way, it is not easy to splash when drinking coffee.

In addition, the exhaust valve can also keep the liquid warm. When you pour hot water into the cup, the air is squeezed into the small holes at the bottom or side of the cup, forming a small space. This space can reduce heat conduction and loss, thereby extending the liquid's heat preservation time.

Variety of coffee cup designs

In addition to the common designs mentioned above, there are many other types of coffee cups on the market, such as those with functional designs such as straw holes and filter holes, and coffee cups made of different materials such as ceramic, glass, and plastic.

Each design has its own specific uses and advantages. For example, a coffee cup with a straw hole is convenient for drinking smoothies or milkshakes; a filter hole is suitable for brewing coffee or tea. And coffee cups made of different materials have different heat preservation properties and tactile properties.

Summarize

In summary, coffee cups usually have two holes. The drinking hole is located near the mouth of the cup and is used to pour beverages; the exhaust valve is located at the bottom or side, which plays a role in balancing pressure and keeping warm. These designs make it more convenient, safer and more comfortable for us to enjoy coffee.

In addition, there are a variety of designs available on the market to meet different needs and personal preferences. Whether it is functional or aesthetic, you can find the ideal coffee cup that suits you.