Summary

Students will be using three ingredients to create a liquid color-works mixture in a jar. This is a fun chemistry project to do with young elementary students around the 4^th of July or New Year’s Eve to get the children excited about fireworks.

Grade Level

Elementary school

Objectives

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

• understand the following vocabulary terms: observation, prediction, outcome, dissolve, mixture and density.

Chemistry Topics

• Observations
• Mixtures
• Density

Time

Teacher Preparation: 15 min

Lesson: 30 min

Materials

• Food coloring (various colors)
• Warm water
• Vegetable oil
• Jars (plastic recommended) – enough for one per student group
• Tablespoon measuring spoons
• Dixie cups – enough for one per student group
• Toothpicks – enough for one per student group

Safety

• Be sure to caution students if using a glass jar. Plastic would be more conducive for this project, but if you are using glass be sure to have extra helping hands for each jar being used.
• Students should wash their hands thoroughly at the end of the activity.
• When students complete the lab, instruct them how to clean up their materials.

Teacher Notes

• This lesson supports students’ understanding of different types of mixtures; students will observe that some liquids have the ability mix together, while others will not.
• The food coloring will dissolve and spread evenly through water but it will not in the oil. When the food coloring is mixed in the oil, small colored droplets will be observed.
• Because oil is less dense than water, students will observe the oil floating to the top of the water in the jar.
• The food coloring drops will move through the oil, and when they are in the bottom portion of the oil, they mix with the water. The heavier colored drops will begin to fall to the bottom, creating many different colors in the jar.
• Students will also be able to experiment with color mixing by utilizing food coloring that creates a new color. Red and blue make purple, etc.
• The teacher should also encourage students to think about density. Once the lesson has been completed, the teacher will discuss again why the oil went to the top! This can be connected to real-world implications by discussing what happens when oil is spilled in the oceans, rivers, or lakes.
• Small student groups or partners work best.
• Teacher should ask for parent support as this lesson is fast paced.
• Students who are at a higher level may be given a data table to collect information (sample is included).
• Lower level students may be paired with another student for this lesson.
• Complete the procedure as a class:
  1. Fill a jar ¾ of the way to the top with warm water.
  2. In a Dixie cup, add 3 tablespoons of oil and 4-5 drops of various colors of food coloring.
  3. Using a tooth pick stir the oil and food coloring mixture to break apart the color droplets so they form smaller ones.
  4. Carefully pour the oil and food coloring into the glass of warm water.
  5. Observe what happens with the colors, oil and water.

• When the lesson is over, cleanup should be handled quickly and carefully with adult assistance. Oil should not be poured down the sink!
• After the activity:
  • Students will then be called to the carpet area. The teacher will reinforce the lesson and discuss the student’s observations, focusing on why the oil and water separated, and why the food coloring mixed with the water but not the oil. The teacher should ask what they think would happen if there was an oil spill in an ocean, lake or river. The students will discuss and generate answers while the teacher listens. The teacher will create a list on chart paper/white board about the implications of an oil spill in a large body of water.