To help students understand the particulate nature of matter, the second sub-topic in this unit will focus on the effects of energy (moving into or out of a substance) on particle motion and attraction.
Students will first sketch a time/energy versus temperature graph for the change of ice from solid, to liquid, to gas, based on previous experience. Although students are likely to draw a graph showing the continuous increase of temperature as energy is added over time, they will not be corrected. Rather, they will discover their error through investigation. Students will conduct a lab entitled “Icy Hot” in which they measure the temperature of water as it changes from a solid to liquid to gas and record the temperature of their sample every 15 seconds making notes on the phase of the sample as well. They will likely be surprised that their data includes two plateaus in temperature. Post lab discussion will focus on the difference between thermal energy (Eth) and phase energy (Eph). Thermal energy will be discussed as a type of kinetic energy, namely, the collective motion of all the particles in a substance. Phase energy will be discussed as a type of potential energy, namely, the energy stored in the attraction between particles (intramolecular forces). Students will be instructed to modify the map they created during subtopic #1 to include phase energy. They will then be tasked with making a time (energy added) versus temperature graph from the data collected in the “Icy Hot” lab, labeling the graph with the phases of matter observed at various points of the lab, and describing the changes in thermal energy (Eth)/particle motion and phase energy (Eph)/particle attraction for each region of the graph. Next, students will read “Heating and Cooling” to reinforce what they have learned in the “Icy Hot” lab and can be applied in subsequent activities. Finally, students will conduct a “Cooling Curve of Different Substances” lab in which students will record the temperature of two acids as they change from liquid to solid. Students will use Google Sheets to make a double line graph of their data from this lab and produce a narrated presentation in which they will compare and contrast the cooling curves of the two acids. In the presentation, students will discuss the differences in 1) energy and time and 2) particle motion and arrangement.
Of the technologies discussed in the last two units (global community data and presentations) presentation best fits this lesson because time and temperature data are not readily available, requiring students to collect data experimentally. Presentations are an effective way for students to share collected data and describe their understanding of that data. Posting the presentations allows students to view one another’s work and learn from their peers.
Learners will be able to:
- Produce a heating or cooling curve from experimental data.
- Label various regions of a heating or cooling curve with the appropriate state of matter.
- Describe the thermal energy (particle motion) at each region of a heating or cooling curve.
- Describe the phase energy (intermolecular attraction) at each region of a heating or cooling curve.
After analyzing data from the “Icy Hot” lab, discussing the differences between phase energy (Eph) and thermal energy (Eth), labeling “Icy Hot” graphs with Ephand Eth, reading “Heating and Cooling” , and conducting “Cooling Curve of Different Substances” lab, make a multiline graph of temperature vs. energy for the acids in the lab using Google Sheets. Then, use Educreations to make a narrated presentation in which you label the phase(s) present in each region of the graph and compare and contrast the graph of each acid with respect to 1) energy and time and 2) particle motion and arrangement (intermolecular forces). Take screenshots of images you want to use in your presentation (your graph(s), for example) to upload them into Educreations. This program will allow you to record your voice and also use a “pen” to write on the screen. Although it is possible to use a mouse to write, I would recommend using a tablet if possible. Other screencasting applications that allow for writing on the screen, may also be used , as long as you can share the presentation with me (and eventually, your classmates).
Link to Google Doc of Assignment:
Example of activity completed with Educreations