2. Science Standard 1: The Nature of Science and Technology Indicator 3.1.2 - Participate in different types of guided scientific investigations, such as observing objects and events and collecting specimens for analysis. Taken from - http://dc.doe.in.gov/Standards/AcademicStandards/StandardSearch.aspx Link to activity - http://www.sciencenetlinks.com/lessons.php?DocID=117
3. Definitions Chromatography - a process used for separating mixtures by virtue of differences in absorbency Paper Chromatography- chromatography that uses selective absorption on a strip of paper Solvent - A substance, usually a liquid, capable of dissolving another substance. Soluble - That can be dissolved, especially easily dissolved http://www.thefreedictionary.com/
4. Background Information When water reaches soluble ink on a piece of paper, it carries the components of the ink across the paper. As the water continues to spread, the components of the ink do not all travel with it at the same rate. Some are more soluble in water than others, the more soluble ones travel faster. After a time, the various components are at different distances from the original ink mark, having been separated from one another. Substances in which other substances dissolve, like water, are called solvents. Scientists use chromatography frequently to separate and identify the component parts of a mixture. http://www.sciencenetlinks.com/lessons.php?DocID=117
5. Do blue and yellow make green? In the box you will find plastic cups, blue, yellow and green food coloring and paper towels. Follow the instructions on the next slides to perform an experiment about mixing colors. Record your predictions and observations where indicated, or in your science journal.
6. Do blue and yellow make green? Fill three of the clear cups half way with water Add four drops of blue food coloring to one cup. Mix well. Add four drops of yellow food coloring to another cup. Mix well Pour 1/3 of the blue water and 1/3 of the yellow water into and empty cup. Mix well.
7. Do blue and yellow make green? What color did the blue and yellow mixture make? Write your observations below. ____________________________________________________________________________________________________________________ Do you think this mixture is the same as if you added green food coloring to water? ____________________________________________________________________________________________________________________
8. Are they the same? Try it and find out! Add four drops of green food coloring to the third cup of water and mix well. Was your prediction about the two cups of green correct? Explain your reasoning. __________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________
9. What about black? In the box you will find plastic cups, markers and coffee filters. Follow the directions on the next slides to perform an experiment that dissolves the ink on the coffee filters. Remember to write your predictions and observations in your science journal.
10. What about black? Fill one plastic cup with 1 centimeter of water. Use the black pen to write two lines on the smooth bottom of one coffee filter. Mark one line on each side of the coffee filter. Make sure not to write on the ridged sides. Place the ridged edge of the coffee filter in the cup of water. The marked bottom of the coffee filter should be at the top of the cup and not in the water.
11. What about black? Make a prediction about what you think will happen to the black ink once the water touches it. Write your prediction in your science journal. Record your observations of what is happening to the ink in your science journal. Write one observation every five minutes. It should take about 15 minutes for the experiment to be complete.
12. What about black? What happened to the black ink? ___________________________________________________________ How many colors do you see? ___________________________________________________________ Draw a picture of what the black ink looks like after 15 minutes.
13. Other colors What would happen to other colors using the same experiment? __________________________________________________________________________________________________________________________________________________________________________ Try it!!! Record what colors you used and what happened to the ink marks. _____________________________________________________________________________________________________________________________________________________
14. Assessment When water reached the black ink mark on the coffee filter, it spread out into how many colors? a. 1 b. 2 c. 0 d. 3 or more
