Welcome to week 5 of Camp Yellow Scope: Pigments & Papers! Who's ready to have some fun (and do science!)?
Click here if you’d like to download printable instructions. You can also print out a lab worksheet to record your observations, jot down ideas, and design your own experiments! If you collect your worksheets together from all eight weeks, by the end of the summer you will have your very own Camp Yellow Scope notebook!
Experiment 1: Go Green!
Do you know what the three primary colors are? That's right - red, yellow, and blue. All other colors can be made by mixing these three colors together in different combinations.
What do you get when you mix blue and yellow together? …………
Did you say green? That's correct. But have you ever wondered if you can "un-mix" green to get blue and yellow again?! In this week's experiments, we are going to try to do just that. Get ready to amaze your friends and family with some pretty cool science.
Let’s get started!
Clear a space on the kitchen counter, your desk, or the picnic table in the backyard. Put on some clothes that can get messy, and get ready to un-mix dyes!
Congratulations, campers! You un-mixed a mixture of green dye.
What’s going on?
The technique you just used to un-mix green color is called paper chromatography. When the water touches the paper, it travels up through a process called capillary action. (You learned about that in last week's experiments with the celery!)
When the water reaches the green dye line, it pulls the dye along with it and separates out the different colors that make up the green dye mixture.
Why do some colors move further than others?
In this way, the different colored dyes in the green food coloring are separated, or un-mixed!
Adding salt to the water changes the properties of the water. It makes it more attractive to some types of dyes. Some dyes move faster in salt water than in plain water. This means that for certain dyes, like the green food coloring we used, that salt water gives a better separation of colors.
The final paper with separated colors is called a chromatogram. Scientists use the terms stationary phase for paper (because it doesn’t move) and mobile phase for water (since it moves!)
Why does it matter?
Can you think of some applications of paper chromatography from your daily lives?
You own it!
Test yourself: True or False
1. False. Chemical reactions cannot be un-mixed because during a chemical reaction the individual components change and form new molecules. Mixtures, which do not change when combined, can be un-mixed.
We hope you had fun separating dyes. Next week we'll have some fun with lemons! So check back next Tuesday for new experiments and more summer science fun!
We'd love to see how your experiments turned out! Share your photos or videos:
For more exciting experiments, check out our science kits on the SHOP tab of our website!