STATES OF MATTER – THERMAL ENERGY
PURPOSE
Matter consists of atoms and molecules and all substances consist of matter. Changing the state
of a substance requires energy. Adding or removing thermal energy from a substance causes a
change of state. Energy affects the attraction between the atom or molecules and their rate of
movement. A substance’s temperature determines whether it occurs in a solid, liquid or gas
state.
A substance changes from a solid to a liquid at its melting point, from a liquid to a gas at its
boiling point, and from a liquid to a solid at its freezing point. A different amount of energy is
needed to change the state of different substances. For example, it takes more energy to melt a
solid metal into a liquid than to melt an ice cube into water.
In this virtual lab you will examine how energy affects the state, the atomic or molecular activity,
and the temperature of a substance.
QUESTION
How does thermal energy affect the state of a substance?
PROCEDURE
1. Go to the website below.
http://www.glencoe.com/sites/common_assets/science/virtual_labs/E17/E17.html
2. Click the Video button. Then click Play on the video controller. Watch the video about
melting and boiling points of substances. In the space below, write a summary of the video:
3. When you select the Water, Mercury, or Iron buttons, the selected substance appear in its
solid form inside the Energy box. The Energy box is able to add thermal energy to the
substance or remove it from the substance at a constant rate. Inside the Energy box, a sensor
senses the temperature of the substance.
Water
Predict what will
happen to the state of
the substance, the
atom activity and the
shape of the graph
when thermal energy
is ADDED
Click the Heat
button on the Energy
box. Observe what
happens to the state of
the substance, the
atom activity, and the
temperature of the
substance. Sketch or
describe your results
Click the Graph
button to see a
printout of a
temperature versus
time graph that shows
what happened when
heat was added to the
substance. Sketch
the graph
Click the Heat
button on the Energy
box. Observe what
happens to the state of
the substance, the
atom activity, and the
temperature of the
substance. Sketch or
describe your results
Mercury
Iron
Click the Graph
button to see a
printout of a
temperature versus
time graph that shows
what happened when
heat was added to the
substance. Sketch
the graph
Predict what will
happen to the state of
the substance, the
atom activity and the
shape of the graph
when thermal energy
is REMOVED.
Click the Cool
button on the Energy
box. Observe what
happens to the state of
the substance, the
atom activity, and the
temperature of the
substance. Sketch or
describe your results
Click the Graph
button to see a
printout of a
temperature versus
time graph that shows
what happened when
heat was added to the
substance. Sketch
the graph
Click the Cool
button on the Energy
box. Observe what
happens to the state of
the substance, the
atom activity, and the
temperature of the
substance. Sketch or
describe your results
Click the Graph
button to see a
printout of a
temperature versus
time graph that shows
what happened when
heat was added to the
substance. Sketch
the graph
Other Observations/Questions/Comments
Questions
1. After observing heat being added to each substance, were your predictions correct or
incorrect? Explain.
2. After observing heat being removed from each substance, were your predictions correct
or incorrect? Explain
3. What do the horizontal portions of the graph represent? When heat is added to or
removed from the substance and the temperature remains the same, when is the thermal
energy going? Why?
4. Determine the approximate melting, boiling and freezing points of the substance by
reading the graph. Record this data in the table.
Substance
Melting Point (C)
Boiling Point (C)
Freezing Point (C)
Iron
Mercury
Water
5. Why do you think it would be impossible to contain gaseous iron inside of a container?