Are you looking for fun STEM activities to do with your daughter at home but not sure how to get started? Our STEM Challenge of the Month is the perfect starting place! Each month, we will introduce different STEM-based experiments and activities that any family can do at home using common household items. Join your daughter while she explores, creates, and learns about STEM activities while having fun and building confidence. Read on to learn more about the February Challenge and get ready to STEM Like a Girl!
Marker Chromatography Experiment
Background:
Have you ever thought about what makes markers different colors when you draw? These various colors come from different molecules, or chemicals, that make up the ink. Each color has its own unique combination of ink molecules. Molecules have different sizes and some are heavier than others so they behave differently. Scientists can separate different molecules using a method called paper chromatography. The molecules (in this experiment the ink from the markers) are placed on a piece of filter paper and exposed to a solvent, a liquid that the molecules dissolve in. As the solvent (for example water or isopropyl alcohol) absorbs up the filter paper, it takes the soluble part of the ink molecules with it. The soluble molecules move up the paper at different rates. When this happens, the different colors in the ink become visible. How far up the paper the molecules travel is related to their size so that smaller particles move farther than heavier ones.
How will your markers behave when you put them to the Marker Chromatography Test?
Materials:
- Water color markers (we found the cheap ones from the Dollar Store work best)
- White coffee filter
- Glass
- Water
- Pencil
- Binder clip
- Permanent marker
- Isopropyl Alcohol (rubbing alcohol, optional)
- Marker Chromatography Experiment Test Sheet
Methods:
Test #1
- Download and print the Marker Chromatography Experiment Test Sheet to record your predictions and observations.
- Cut your coffee filter into a rectangle approximately 2 inches wide.
- Draw small circles with your pencil just above the bottom of the filter (picture 1).
- Color in each circle with a different color water color marker (picture 2, note: chose both primary and secondary colors and be sure to include either black or brown).
- Using the binder clip and pencil to hold the filter in place, lower it into your glass so that it hovers just above the bottom of the glass (picture 3).
- Carefully pour water (your solvent) into the glass so that it just covers the bottom of the filter. Be sure not to pour above the circles or along the length of the filter (picture 4).
- Start your observations (picture 5).
- After several minutes, remove the coffee filter and allow it to dry (picture 6).
Test #2
- Repeat steps 1-4 above but color one circle with a water color marker and the other with a permanent marker (picture 1).
- Place each strip in a separate glass and secure in place.
- Pour water (solvent #1) into the bottom of one glass (pictre 2). Optional: Pour isopropyl alcohol (solvent #2) into the bottom of the other glass (picture 3).
- Start your observations.
- After several minutes, remove the coffee filters and allow to dry (picture 4).
Observations:
- What happens to the colors as the water wets the paper?
- How do the different colors react differently? Which starting colors are made up of one ink color and which separate into different colors?
- Do the water color markers react differently than the permanent markers when placed in water?
- Optional test: How do the markers behave when placed in different solvents (water vs. isopropyl alcohol)?
- Did your results agree with your predictions or were you surprised?
- What additional experiments can you try using paper chromatography?
