A pipette is a tool scientists use to move liquids from one place to another. Some pipettes are used to transfer tiny amounts of liquid, and some are used to transfer large amounts. Do you have a turkey baster in your kitchen? A turkey baster is a great big pipette! You may have used a smaller, plastic pipette before for a science or art activity. Here is a picture of a common disposable pipette.
In this activity you will use a pipette to transfer red, yellow and blue tinted water to an ice cube tray, and play with color mixing.
Supplies:
3 plastic straws or pipettes
1 cup of red tinted water (try 15 drops of food coloring per cup)
1 cup of blue tinted water (try 5 drops of food coloring per cup)
1 cup of yellow tinted water (try 10 drops of food coloring per cup)
1 white or translucent ice cube tray (or several white or clear cups)
Instructions:
1) Practice using your disposable pipette or straw to pick up and release water.
How to use a disposable pipette:
Squeeze the bulb. Lower the pipette tip into the liquid. Release the bulb and the liquid will rise into the pipette. Take the pipette tip out of the liquid. The liquid will stay in the pipette. Squeeze the bulb to release the liquid.
How to make a pipette from a thin (easy to bend) plastic straw:
Lower the straw into the liquid. Fold the top of the straw over and pinch to hold it in a folded position. Keep the fold in the straw and take the straw out of the liquid. The liquid will stay in the straw. Lift the fold to release the liquid.
How to use a plastic straw for transferring liquids:
Lower the straw into the liquid. Firmly cover the open top of the straw with your thumb or index finger - whichever is more comfortable. Keeping the opening firmly covered, lift the straw out of the liquid. The liquid will stay in the straw. Uncover the top of the straw to release the liquid.
If you don't have a pipette or a straw on hand, no problem! Try a measuring spoon in the 1 teaspoon to 1 tablespoon range. If you are using spoons, it will be easier to have your colored water in shallow bowls rather than cups.
2) Use your straw or pipette to transfer red, blue and yellow colored water to the ice cube tray. Add red water to the upper left well. Skip a well and add yellow water. Skip another well and add blue water. Now try mixing colors to fill in the empty wells and make a rainbow!
3) Rinse your ice cube tray in the sink when you are ready to start over. Starting with the primary colors, try making the secondary colors.
Can you identify which are the complementary colors? If you are having fun, try to make the tertiary colors too. There are many free color wheels available online for reference. I have included a few you may find useful. The links to these color wheels can be found here: first, second, third.
4) Have a little fun. Can you make the color of your favorite flower? How about a color that looks cold or a color that makes you feel happy? What would be a good color for a "magic potion"?
5) Cleanup: safe to rinse down the drain. Be aware that food coloring may stain light surfaces or clothing.
If you are interested in learning about color theory, here is a link to help you get started. The bare bones are: a primary color (red, blue or yellow) is one that cannot be made by mixing other colors. A secondary color (orange, green or purple) is made by mixing two primary colors, and a tertiary color is made by mixing one primary and one secondary color. Complementary colors are found opposite one another on a color wheel, and have the highest contrast with one another. Analogous colors are found adjacent to one another on the color wheel and blend in with one another the best. What do you think? Compare these two patterns in your ice cube tray: red - orange - red versus blue - orange - blue. Does the orange stand out more when it is flanked by red or blue?
Click below to download a pdf of the Pipetting a Rainbow DIY science kit for easier printing.
Make messes, have fun and spread science joy!