A standing wave pattern is a vibrational pattern created within an object or in this case a slinky, when the vibrational frequency of the slinky causes reflected waves from one end of the slinky to interfere with incident waves from the other side. This interference occurs in such a manner that specific points along the slinky appear to be standing still. Such patterns are only created within the slinky at specific frequencies of vibration. These frequencies are known as harmonic frequencies. At any frequency other than a harmonic frequency, the interference of reflected and incident waves leads to a resulting disturbance of the slinky that is irregular and non-repeating. In this specific photo the blurriness is depicting these waves that are being sent through from side to the other.

Sipping a drink through a straw might seem simple. But you are actually using some fancy air pressure changes to move your beverage. The sipping action occurs when you lower the air pressure in your mouth, which allows the atmospheric pressure to push the liquid up the straw. This photo shows a straw with Gatorade held inside. I'm also covering the top of the straw with my finger which limits the flow of molecules into the straw. The liquid stays in the straw because there is a difference in pressure between the inside of the straw and the outside. The air pressure on the outside pushes the liquid up the straw and holds it there. The liquid remains at the bottom of the straw due to gravity, which is pulling it down.