Students in Lauren McHale’s fourth-grade class at Winthrop welcomed Mepham High School chemistry teacher Lee Mattes to discuss physical and chemical changes in matter on Nov. 7.
    
Mr. Mattes, whose daughter Ruby is in the class, discussed the differences between physical and chemical changes. To showcase a physical reaction, he poured rubbing alcohol and acetone on a tile to show the difference in evaporation times.
    
“When you have different substances, they’re going to have different physical and chemical properties,” Mr. Mattes said. “It’s very rare that they’re the same.”
    
Mr. Mattes then put alcohol into a coffee can and shook it. He had a lit candle on a meter stick, and he brought the candle to the can, which caused the cover to pop off. He also discussed indicators with the students, and he stressed that labeling beakers and other items in the lab is vital to ensure safety, as is wearing protective goggles.
    
“He was able to demonstrate the difference between physical and chemical changes in matter for the students to understand,” Mrs. McHale said. “This will help us as we move forward with our lesson.”