Door

A door is a moving wall.

It lets you go in and out. It also keeps you safe.

Some doors swing on hinges. Other doors can slide. Some doors even fold.

Doors can be made of many things. Many are made of wood. Some are made of metal. Some are even made of stone.

Doors can do many jobs. They can keep out noise. They can block fire. They can also let in light.

Some doors have locks. You might use a key to open them. This helps keep people out.

Long ago, people made doors of wood and gold. Doors help us live in our homes.

A door is a movable barrier. It lets people enter or exit a space.

The opening in the wall is called a doorway.

Most doors provide security. Many use locks so only certain people can enter.

Doors can move in many ways. Most use hinges to swing open. Some doors slide on a flat path. Others fold or spin.

People use doors for many jobs. They provide privacy. They can block noise or fire. Doors also let in light or air.

Doors have a long history. Very old doors were made of wood. Some were even covered in gold.

In dry places like Egypt, doors were simple. In other lands, builders used frames. They used vertical boards called stiles. They also used horizontal pieces called rails.

In some places, people made doors from stone.

Some doors are very special. The largest doors are at NASA. They are at the Vehicle Assembly Building. These doors are very high. They help build space ships.

A door is a movable barrier that lets people enter or exit a space.

The opening in the wall is called a doorway or a portal. Most doors help keep things safe by controlling who can pass through. They are often panels that fit into the doorway of a building or a vehicle.

Doors can do many extra jobs besides letting people in. They can provide privacy or separate different rooms. They also help control light, air, and noise. Some doors even help block the spread of fire.

Doors move in several different ways to work correctly. Most doors use hinges to swing open at an angle. Some doors slide along a flat plane instead of swinging. Other doors might fold in angles or spin around a center point.

Many doors also have locks so only certain people can use a key. People might use a knocker or a doorbell to announce they are there. This makes it easy to manage who enters a home or a building.

Humans have been making doors for a very long time. The earliest recorded doors appear in paintings of Egyptian tombs. These were often single or double doors made of one piece of wood.

In very old times, doors were made of timber like olive wood. Some were even covered in gold or silver. Archaeologists found two doors that are over 5,000 years old near Zürich, Switzerland. In some places like Syria, people made doors out of stone because wood was hard to find.

History shows us many amazing ways doors were built. In the first century AD, Heron of Alexandria made the first automatic door. Later, a foot-sensor door was made in China for an emperor's library.

During the Middle Ages, many beautiful bronze doors were made. One famous set is the "Gates of Paradise" by Ghiberti in Florence. These were finished around the year 1452. These metal doors were often decorated with beautiful shapes and figures.

Today, we see doors of all different sizes and styles. Most people use a single-leaf door in their homes. You might also see a double door with two panels.

There are even half doors, which are called Dutch doors. These are split in the middle so the top can open while the bottom stays shut. Some doors are even huge, like the ones at NASA's Vehicle Assembly Building. These massive doors help engineers work on space vehicles.

A door is a movable barrier designed for ingress and egress. Ingress refers to the act of entering a space. Egress refers to the act of exiting a space.

The opening in a wall that the door fills is called a doorway or a portal. The primary purpose of a door is to provide security. It does this by controlling access to the portal. Doors are typically panels that fit into the frame of a building, a room, or a vehicle.

Doors move through several different mechanical processes. Most commonly, they are attached by hinges to swing at an angle. Some doors operate by sliding on a plane parallel to the frame. Others may fold in angles on a parallel plane. Some doors even spin along an axis at the center of the frame.

Many doors incorporate locking mechanisms. These allow only specific people to enter, often using a key. People also use devices like knockers or doorbells to announce their presence to those inside.

Beyond basic access, doors serve many secondary functions. They provide privacy by preventing unwanted attention from outsiders. They can separate areas that have different functions. Doors also manage the environment inside a building. They can allow light to pass through or control ventilation to manage air drafts. This helps to heat or cool an interior more effectively. Furthermore, doors can dampen noise or help block the spread of fire.

Construction methods vary based on the materials used. A standard door often uses a frame and panel design. This includes vertical boards called stiles and horizontal pieces called rails. The hanging stile is the vertical board that is attached to the frame. The meeting stile is the vertical board that meets the other door in a double-door setup. The horizontal pieces include the top rail, the bottom rail, and middle rails. These rails hold the panels, known as tympana, which are set into grooves within the stiles and rails.

History shows a long evolution of door design and material. The earliest recorded doors appear in Egyptian tomb paintings. These were often single or double doors made of single pieces of wood. In Egypt, the dry climate meant doors did not need to be framed against warping. In other regions, framing was necessary to keep the wood stable. Archaeologists have discovered doors near Zürich, Switzerland, that are over 5,000 years old. Ancient builders used various timbers, including olive, elm, cedar, oak, and cypress.

Technological milestones have changed how doors function. In the first century AD, Heron of Alexandria created the earliest known automatic door. Much later, the first foot-sensor-activated automatic door was built in China. This was installed for the library of Emperor Yang of Sui between 604 and 618 AD.

During the Middle Ages, bronze became a popular material for decorative doors. One famous example is the "Gates of Paradise" in Florence. These gilded bronze doors were completed by Ghiberti between 1425 and 1452.

Doors also hold deep symbolic and social meaning. Receiving a key to a door can signify a change in status. It can represent a transition from an outsider to an insider. In literature and art, doors often serve as metaphors for change. They can be ritualistic or aesthetic objects. Even the size of a door can be significant. For example, NASA's Vehicle Assembly Building contains four of the largest doors in existence. These massive doors were built to support the assembly of Apollo Saturn vehicles and Space Shuttle operations.

Today, we categorize doors by their specific configurations. A single-leaf door is a single rigid panel. A double-leaf door, or double door, uses two adjacent panels hinged on each side.

There are also Dutch doors, which are divided horizontally. This allows the top half to open while the bottom remains closed. This design was traditionally used so workers could feed animals without the animal escaping. From small residential panels to massive industrial gates, doors remain essential to how we organize our world.