The Race of Molecules
The Race of Molecules is a Grade 5 science skill from Amplify Science (California) explaining how chromatography separates mixtures. In paper chromatography, a mixture like ink is placed on paper. Dye molecules with strong attraction to the paper move slowly and stay near the start; molecules with weak attraction move faster and travel farther. The different distances create visible separated bands. This Chapter 2 skill helps fifth graders understand separation techniques at the molecular level and connects to the investigation of salad dressings and solutions.
Key Concepts
Imagine a race where some runners get distracted and stop to talk to the crowd, while others run straight ahead. This is how chromatography works.
In this process, a mixture (like ink) is placed on paper. Some dye molecules have a strong attraction to the paper, so they move slowly. Other molecules are more attracted to the water moving through the paper, so they travel fast.
Common Questions
What is chromatography and how does it separate mixtures?
Chromatography separates mixtures based on molecular attraction. In paper chromatography, different molecules move at different speeds across paper—those with weak attraction travel farther, those with strong attraction stay closer to the start.
Why do some molecules travel farther than others in paper chromatography?
Molecules with weak attraction to the paper travel faster and farther because nothing slows them down. Molecules with strong attraction stick more to the paper and move slowly.
What is the race analogy in The Race of Molecules?
The analogy compares dye molecules to runners in a race. Some runners get distracted and slow down (strong paper attraction), while others run straight through (weak attraction), causing separation over distance.
What mixtures can be separated using chromatography?
Chromatography can separate ink into component dyes, food coloring into individual pigments, and other liquid mixtures. Each component separates based on its unique molecular attraction properties.
How does chromatography relate to the salad dressing investigation in Amplify Science Grade 5?
Chapter 2 uses chromatography as a method to investigate mixture components by separating them based on differences in molecular attraction to the paper medium.