Question

everything around us is made of matter—your clothes, the trees, even the water you drink! we divide matter into four major categories, which are called the four states of matter: liquid, gaseous, solid, and plasma. however, we will focus on the first three. whatever the state of matter may be, all matter is made of tiny particles called atoms. these particles are too tiny to see with the naked eye; theyre even too small to see with a regular microscope. if you line up a million atoms next to each other, they will be as thick as a single piece of human hair. so, we can only look at atoms through very powerful tools, one of them being the “scanning tunneling” microscope.
how do we know?
we can easily see liquids and solids around us, but most gases arent visible. we cant see the air around us, but it is still made of atoms that constantly move around freely in space. how can we tell?
take a balloon, for example. when we pump air into a balloon, it visibly inflates. that means that gaseous matter is filling the balloon and taking up space. the more air we blow into the balloon, the bigger it gets. therefore, we can observe the way gas moves around space. in the same way, inflatable pool toys also fill with air so that they can float on water. when we fill the plastic shells with air, the toys take shape. since air is less dense than water, the pool toys can rest on the water without sinking. and then we can enjoy a sunny day while floating in a pool!
vocabulary activity
d gas
2 why does the author describe the balloon and inflatable pool toys filling up with air?
a in order to explain that it is impossible to observe the way gas moves around space
b in order to explain that air is not made of atoms that take up space
c in order to explain that air is made of atoms that take up space even though air is invisible
d in order to prove that these are fun objects to inflate
3 usually, atoms move slower in solids than they do in liquids. which evidence from the passage best supports this statement?
a solids, liquids, and gases can all undergo the process of diffusion.
b diffusion is the movement of particles from a higher concentration to a lower concentration.
c the atoms in gas move the fastest

Explanation:

1. For question 2: The text uses the balloon and inflatable pool toys as examples to show that air (a gas) takes up space, since inflating them makes them expand and take shape, proving air occupies space even if invisible.
2. For question 3: The passage states that gas moves around space freely, while solids and liquids have more restricted particle movement, which supports that atoms move slower in solids/liquids than gases. Option C is not mentioned, option B is a definition not related to the speed claim, option A is incorrect as solids do not undergo diffusion like liquids/gases easily.

Answer:

1. C. in order to explain that air is made of atoms that take up space even though air is invisible
2. C. The atoms in gas move the fastest