Curricula

Food Dye Electrophoresis

In this lesson, students will explore the process of agarose gel electrophoresis to figure out which food dye molecules give Skittles® candy their colors. Initially, students predict the direction of dye migration based on their understanding of how size and charge govern the movement of molecules. Students then extract food dye from Skittles®, load these samples into an agarose gel using a micropipette, and run a current through the gel to separate the dye molecules. They will be able to predict, observe, and compare the movement of their extracts with known food dyes. To conclude, students will make a claim about which food dye(s) is/are present in their Skittle® and support it using evidence from their gel and reasoning about the scientific principles behind electrophoresis. This lab is helpful to complete before other labs involving gel electrophoresis such as DNA Forensics and PCR related labs.

In the online version of the lesson, students make their predictions and then watch a video of dye being extracted from Skittles®. They use sample images from gel electrophoresis to inform their CER.

Learning Objectives

  • Perform agarose gel electrophoresis to separate food dye molecules based on charge and size
  • Predict the behavior of a molecule on an agarose gel based on its size and charge
  • Make a claim about which dyes are used to make Skittles and support it using evidence and reasoning

Prior Knowledge

  • Relationship between atoms and molecules
  • Difference between positively and negatively charged molecules
  • Using micropipettes to measure and transfer small volumes

In order to access any Curriculum resource, please or sign up if you haven't already done so.

In order to access any Curriculum resource, please or sign up if you haven't already done so.

Disciplinary Core Ideas:

PS1.A Structure and Properties of Matter
“…interactions of matter at the bulk scale are determined by electrical forces within and between atoms.”

PS2.B Types of Interactions
“…Attraction and repulsion between electric charges at the atomic scale explain the structure, properties, and transformations of matter….”

Science and Engineering Practices:

Engaging in argument from evidence

Crosscutting Concepts:

Structure and Function”

In order to access any Curriculum resource, please or sign up if you haven't already done so.

Amanda Cherry
Paradise Valley HS
Phoenix, AZ

The curriculum materials are beautifully prepared and easy to understand-thanks for preparing such great resources that are easy to use.

Byron Gougoumis
Burton HS
San Francisco, CA

All Babec labs are well organised and modelled effectively with clear, helpful procedural instructions, easily transposed to the classroom.

Gianne Souza
Lincoln HS
San Francisco, CA

The online resources are SO well done! The best I have ever had. Very little modification to make them clear and easy to follow. I have done two BABEC lessons and they are so well made that they made teaching online fun again.

Heather Johnson
Burlingame HS
Burlingame, CA

When doing the BABEC labs I consistently hear students say they feel like "real scientists."

Marianne Gudmundsson
Glenbrook South HS
Glenview, IL

Well organized and scaffolded; flexible structure and can be used partially or as a whole. This unit can be used as is...superbly written and thought out...incorporates many skills and allows student collaboration and student choice/voice.

Rocky Ng
South San Francisco HS
South San Francisco, CA

Thank you for creating these curriculum materials. I am beyond grateful for the quality lessons, on-the-point figures/videos, and easy-to-navigate biotechnology curriculum.

Thi Ngo
Capuchino HS
San Bruno, CA

The level of support really made the whole process easier and encouraged me to continue incorporating biotech into my curriculum. Thank you for the live assistance during the labs and for responding to inquiries so promptly and with such urgency.

Anonymous Teacher

Really well thought out curricula. Great to see "old" activities that have been re-imagined with lots of consideration to NGSS.

Anonymous Teacher

This was the best educational workshop I have had the honor of attending, and I am so thankful.

Anonymous Teacher

Wonderfully executed. Strengthened my skills. Thank you!!

Anonymous Teacher

BABEC has such a strong positive impact on teachers and students - thank you for your amazing work!