What Is Matter?: Properties and Classification of Matter Interactive Activity: 4-Question Survey

The correct answer is B: a tank filled with compressed air weighs more than an empty tank. Air is matter, and so by definition has weight and takes up space. Many people have the misconception that air is either weightless or will subtract weight from something that it fills. Others may be thrown off by answer c, believing that the outside air pressure might be great enough to “buoy” up the filled tank. Under everyday conditions, however, the effect of the outside air pressure on the weight of the tank is so small as to be negligible.

The correct answer is A: helium. Though it is a gas that is lighter than air, helium does take up space and have weight. Gravity is the name of the force that attracts bodies of matter towards each other. Light and heat are forms of energy and, like gravity, do not have weight and do not take up space.

The correct answer is C: its density. Density is a property associated with the “material kind” of matter referred to in the video, and is a measure of the number of particles of matter per area. The density of matter does not change, regardless of how it is divided. Length, shape, and weight are all properties that have no effect on the density of matter.

The correct answer is A: the false statement is that plasmas make up a small percentage of the visible universe. Ninety-nine percent of what we observe when we look to the skies with a telescope or our naked eye is plasma. The credit for discovering the “fourth state of matter” is given to the English scientist William Crookes, who, in the late nineteenth century, was studying the effect and behavior of gases at low densities inside a tube, when an electric discharge was introduced. He realized that a new state of matter appeared and that an electric current could pass through it. This new state was eventually named plasma in the 1920s by the American physicist Irving Langmuir.