A balloon filled with air is a flexible, inflatable object made from materials like latex or Mylar. When air is blown into the balloon, it expands, creating a round shape. The air inside is held by the balloon's elastic material, which allows it to stretch without breaking. Balloons are often used for decorations, parties, and celebrations. Air-filled balloons can come in various sizes and colors, making them popular for events like birthdays and weddings. They can also be used in games and activities, such as balloon tosses or races. When released, they float away, demonstrating the principle of buoyancy.