Summary

In this lab, students will analyze different scenarios in order to determine if a physical or chemical change has occurred. This lab experience will provide students with the opportunity to record observations, as well as improve their ability to differentiate between physical and chemical changes.

Grade Level

Elementary and Middle School

NGSS Alignment

This lab will help prepare your students to meet the performance expectations in the following standards:

• 5-PS1-4: Conduct an investigation to determine whether the mixing of two or more substances results in new substances.
• MS-PS1-2: Analyze and interpret data on the properties of substances before and after the substances interact to determine if a chemical reaction has occurred.
  
• Scientific and Engineering Practices:
  • Analyzing and Interpreting Data
  • Engaging in Argument from Evidence

Objectives

By the end of this lab, students should be able to

• Describe the meaning of a physical change.
• Describe the meaning of a chemical change.
• Differentiate between a physical change and chemical change.
• Determine if a physical or chemical change has occurred based on the evidence provided.

Chemistry Topics

This lab supports students’ understanding of

• Physical changes
• Chemical changes
• Observations

Time

Teacher Preparation: 20 minutes
Lesson: 1 hour

Materials

• Station 1: 1 apple, plastic knife, plate/tray
• Station 2: 1 plastic cup, baking soda, vinegar, plastic spoon
• Station 3: 1 used match, 1 new match, magnifying glass
• Station 4: 1 small sample of steel wool (about the size of a quarter), vinegar, clear bowl/cup, tweezers, tray/plate
• Station 5: 1 burning candle (tea light works well)
• Station 6: 1 ice cube, clear plastic cup or plate
• Station 7: 1 sheet of paper
• Station 8: 1 lump of clay/Play-Doh

Safety

• Always wear safety goggles when handling chemicals in the lab.
• Students should wash their hands thoroughly before leaving the lab.
• When students complete the lab, instruct them how to clean up their materials and dispose of any chemicals.
• Always use caution around open flames. Keep flames away from flammable substances.
• Always be aware of an open flame. Do not reach over it, tie back hair, and secure loose clothing.
• Open flames can cause burns. Liquid wax is hot and can burn the skin.
• When lighting the match, be cautious with the flame.
• When working with acids (vinegar), if any solution gets on your skin immediately rinse the area with water.
• Do not consume lab solutions, even if they’re otherwise edible products.
• Food in the lab should be considered a chemical not for consumption.

Teacher Notes

• It is helpful to organize the materials at each station on plastic trays.
• I suggest organizing students into partners. Students only need about two-four minutes at each station. 
• Teachers should set the stations up before the students arrive. If there are more student groups than there are stations available, it might be helpful to create two sets of each stations, so that students don’t spend a lot of time waiting, or disengaged.
• Stations tips:
  • Station 1: It might be helpful to have a piece of apple pre-cut, so it can begin to oxidize/turn brown in advance of the students observing it.
  • Station 2: Only small amounts of baking soda and vinegar are needed. The teacher may need to refresh the cup with vinegar several times throughout the lab time.
  • Station 3: Burn one match in advance of the lab. Be sure to tell students that they are NOT burning the fresh match.
  • Station 4: Only a small amount of steel wool and vinegar is needed. Combine these in advance to allow the reaction to get started.
  • Station 5: Caution students about behavior around an open flame. Placing a tea light inside of glass cup/beaker can be helpful.
  • Station 6: Place ice cup in cup or on plate in advance so the melting process can begin.
  • Station 7: Extra paper may be needed.
  • Station 8: N/A.
• Set a timer for 2-3 minutes per station. Alert students that when the timer rings, that they should rotate to the next station.
• There are instruction card printouts available to have on display at each station.
• Instructions for the students are also included in the data table on the student handout.
• An Answer Key document has been provided for teacher reference.