Video Transcript
Which of the following is not a
characteristic that can be used to describe matter? (A) Density, (B) electrical
conductivity, (C) hardness, (D) thermal conductivity, or (E) visibility.
This question is asking us to
determine which characteristic cannot be used to describe matter. Matter is anything that has mass
and volume. All things are made up of
matter. All matter is made up of atoms. Atoms are the basic units of matter
and can be used to understand properties of matter.
The five answer choices listed are
examples of physical properties. A physical property is a measurable
property that can be observed without changing the identity of the substance. Let’s look more closely at each of
the properties listed.
Answer choice (A) is density, which
can be defined as an object’s mass divided by its volume. In other words, it is the amount of
matter per space. Let’s take, for example, two
objects with the same volume of one cubic meter. The first object has a mass of one
kilogram. The second object has a mass of 10
kilograms. Because there is a higher mass per
volume, the second object has a higher density. This is a physical property that
describes matter. For example, we could use density
to describe the difference between two different types of matter. This question is asking us to
identify which is not a characteristic used to describe matter. So we can eliminate answer choice
(A).
Answer choice (B) is electrical
conductivity. Electrical conductivity is the
ability to conduct an electric current. For example, a metal wire has a
high electrical conductivity. Metals have a high ability to
conduct electric current, whereas a cloth shirt would not have a high ability to
conduct electric current. This is an observable property used
to describe matter, so this is not the correct answer. We can eliminate answer choice
(B).
Answer choice (C) is hardness. Hardness of matter can be described
as a measure of a material’s strength and resistance to scratching. For example, a diamond is described
as having a very high hardness since it cannot be scratched easily and is very
strong. However, graphite, which is the
material in a pencil, has a very low hardness, which is why it is soft enough to
write on paper. This is a physical property used to
describe matter. We can eliminate answer choice
(C).
Answer choice (D) is thermal
conductivity. Thermal conductivity is the ability
to conduct thermal energy. In other words, it is a material’s
ability to conduct heat. Let’s take for example a household
metal pot. The metal has a high thermal
conductivity and heats up quickly. It conducts heat easily and can
heat up things like water, which makes it a very useful material to us. However, a material such as plastic
is not a good conductor of heat, which makes it an effective handle to protect us
from the heat. Thermal conductivity is a physical
property used to describe matter. We can eliminate answer choice
(D).
Finally, answer choice (E) is
visibility. Visibility is the ability of
something to be seen by the human eye. Much of the matter in our daily
lives can be seen. Take, for example, a glass of
saltwater. While we can see the glass and
water, we cannot see all of the matter present, like the salt particles dissolved in
the water. Visibility is not an effective
characteristic to describe matter, since not all matter can be seen. Therefore, answer choice (E) is the
correct answer.
So the characteristic that cannot
be used to describe matter is answer choice (E), visibility.
