Page ______

HEAT IT UP!

You have learned the differences between the three states of matter. Acid precipitation can exist as a solid (snow, hail), liquid (rain), or a gas (water vapor). But what would happen to a substance’s state if its temperature is increased? For instance, solid metals that make up everyday materials like a paperclip can be melted into a liquid and shaped under extreme temperatures. Even oxygen can lose enough heat energy to be turned into a liquid! In this investigation, you will analyze data involving a change in state as temperature increases.

Objective: Student will analyze data in order to provide evidence thatatoms and molecules are in constant motion.

Materials (per group)

beaker, 250 mL

burrette clamp

ice, 5 cubes

ring clamp

water 50 mL

insulated pad

wire gauze

ruler

heat source, lab burner*

safety goggles

ring stand

graph paper

EasyTemp probe

TI–84+ Silver Edition

Procedures: Activity 1: Prediction

  1. Predict what will happen to the ice if heated.

______

  1. Predict what will happen to the motion of molecules as the ice is heated.

______

Activity 2: Investigating the Heating of Ice

What will happen to the ice when heat energy is added? Let’s conduct and investigation to find out the answer. Science investigations always begin a problem question.

  1. Read the problem question for this investigation.

Problem: What is the effect of time of heating on the temperature?

  1. Identify the independent (manipulated) and dependent (responding) variables for the investigation.

Independent (manipulated): ______

Dependent (responding): ______

5. Read the procedures, “Heating Ice.”

6. Reread the procedures and highlight the verbs.


7. Review the procedure and circle all steps that involve recording data.

  1. Before you can complete the procedures, you must construct a chart for recording data. Examine the charts in Figure 2 and circle the one that would be best for this investigation.

Figure 2

Time HeatThermal energy Time Time Temperature

  1. Justify your selection using prior knowledge and information from the procedures.

______

  1. Construct the chart. Include all necessary information.
  2. Conduct the investigation.
  3. Construct an appropriate graph on a sheet of graph paper to identify patterns within the data. Your graph should include:

_____• a title that refers to the problem and includes

the independent and dependent variable.

_____• the independent variable labeled along the

horizontal axis.

_____• the dependent variable labeled on the vertical axis

_____• units of measure with each variable.

_____• an appropriate scale used on each axis.

_____• the data displayed in an appropriate graph.

______Circle the point on your graph where all of the ice

melted.

______Place a box around the point where the water began to boil.

Activity 3: Analyzing the Data

  1. Explain why it is important to graph data from an experiment.______
  1. Identify the relationship between the time of heating(heat energy) and the temperature of the water. Use information from the graph to support your response.

______

  1. The melting point of water is OºC. Determine the temperature at which the ice completely melted. Explain why this temperature is greater than the melting point of ice.

______

  1. Look at your graph. You should see that around 100ºC the temperature remains constant. Explain what was happening to the water when the temperature hit this plateau.

______

Class Discussion

a. Examine the predictions you made in Activity One. As temperature (heat energy) is increased in the investigation, what inferences can you make about the motion of the molecules within the water?

______

b. View the animation. Does this animation support the results of the investigation?

______

c. Was it helpful?

______

Analysis

1. Heat is the energy of moving molecules and atoms. When you heat something its molecules move faster. Figure 3 shows the molecules of water before heating and after it has been heated for a short time period.

  1. Count the molecules and record.

Beaker A ______Beaker B ______Beaker C ______

b. Compare the arrangement of molecules in Beaker A and B.

______

c. Use information from the diagram to determine the cause of the change in arrangement

of the molecules.

______

d. Draw the arrangement of molecules in Beaker C if we continue to add heat to Beaker B until the temperature is 100ºC.

e. Justify your arrangement of the molecules based on your prior knowledge and evidence from the investigation.

______

F. Identify the state of matter occurring at each number in the diagram. Label solid, liquid, or gas.

Debate Diary : What inferences could you make about the motion of molecules during the formation of acid precipitation? ______

______