PHASE CHANGE LAB

Problem: What happens to the temperature during phase changes? Introduction: Write complete sentences about facts and what you know already about phase changes. Hypothesis: If I graph temperature vs time then I can predict where phase changes occurred. Materials 1 cup of ice (1)thermometer (1) beaker (1)hot plate (1)safety glasses

Procedure: Fill beaker ¾ full of ice Place beaker on hot plate at medium setting Record starting temperature in degrees Celsius. Record temperature every minute until ½ water is boiled away. Graph temperatures as you record temperatures

Temperature Data Time (Minutes) Temperature (C)

Conclusion- Analysis- Restate your hypothesis indicating if it was correct or not Analysis- What did you learn in the experiment? What did you figure out due to the graph? This means analyze the graph. Describe the unusual circumstances and the effect they had on the experiment. State any further questions you may have. What happens to the temperature of freezing water when you continue to remove energy through cooling? What does the slope of the graphs represent? How does the slope that shows water boiling compare to the slope before the water starts to boil? Why does the slope differ during those two periods?

The particles that make up solids, liquids and gases are in constant motion. Adding or removing energy causes changes in the movement of these particles. Using this idea, describe in terms of motion of the water molecules what is happening when the slope changes in your graphs. (Answer this in (1) 5 sentence paragraph)