Huffy Disney Frozen Girls’ Inline Folding Kick Scooter by Huffy, Blue

Blue is one of the three primary colours in the RYB colour model (traditional colour theory), as well as in the RGB (additive) colour model. It lies between violet and cyan on the spectrum of visible light. The term blue generally describes colours perceived by humans observing light with a dominant wavelength that's between approximately 450 and 495 nanometres. Most blues contain a slight mixture of other colours; azure contains some green, while ultramarine contains some violet. The clear daytime sky and the deep sea appear blue because of an optical effect known as Rayleigh scattering. An optical effect called the Tyndall effect explains blue eyes. Distant objects appear more blue because of another optical effect called aerial perspective.

Blue has been an important colour in art and decoration since ancient times. The semi-precious stone lapis lazuli was used in ancient Egypt for jewellery and ornament and later, in the Renaissance, to make the pigment ultramarine, the most expensive of all pigments. In the eighth century Chinese artists used cobalt blue to colour fine blue and white porcelain. In the Middle Ages, European artists used it in the windows of cathedrals. Europeans wore clothing coloured with the vegetable dye woad until it was replaced by the finer indigo from America. In the 19th century, synthetic blue dyes and pigments gradually replaced organic dyes and mineral pigments. Dark blue became a common colour for military uniforms and later, in the late 20th century, for business suits. Because blue has commonly been associated with harmony, it was chosen as the colour of the flags of the United Nations and the European Union.

In the United States and Europe, blue is the colour that both men and women are most likely to choose as their favourite, with at least one recent survey showing the same across several other countries, including China, Malaysia, and Indonesia. Past surveys in the US and Europe have found that blue is the colour most commonly associated with harmony, confidence, masculinity, knowledge, intelligence, calmness, distance, infinity, the imagination, cold, and sadness.

Frozen may refer to:

• the result of freezing
• a paralysis response in extreme cases of fear

The Huffy Corporation is a supplier of bicycles with headquarters in Dayton, Ohio, United States.

Inline is commonly used to mean "in a line", "aligned" or "placed within a line or sequence". Topics that feature "inline" in their names include:

• Inline citation (here meaning "within a line of text")
• Inline engine
• Inline hockey
• Inline skating

A kick is a physical strike using the leg, in unison usually with an area of the knee or lower using the foot, heel, tibia (shin), ball of the foot, blade of the foot, toes or knee (the latter is also known as a knee strike). This type of attack is used frequently by hooved animals as well as humans in the context of stand-up fighting. Kicks play a significant role in many forms of martial arts, such as capoeira, kalaripayattu, karate, kickboxing, kung fu, wing chun, MMA, Muay Thai, pankration, pradal serey, savate, sikaran, silat, taekwondo, vovinam, and Yaw-Yan. Kicks are a universal act of aggression among humans.

Kicking is also prominent from its use in many sports, especially those called football. The best known of these sports is association football, also known as soccer.