Guiding Question: How can you determine the strength of an acid or a base uasing a cabbage indicator?
Hypothesis: I believe that when the litmus paper is put into an acid, it will turn red, and if it put into a base, it would become blue. The intensity of an acid or a base can be determined by the intensities of the two colors shown on litmus paper. Also, the neutral solution will probably turn green. Some examples of substances that will probably turn out to be acids will be lemon and oranje juice, HCl solution. Some liquids that I am expecting to be bases are most of the cleaning supplies that could be found around the house. Substances that are expected to act very gently, and with little affects, such as baby oil, will probably go green, and turn out to be neutral.
The Variables: The controlled variable of this lab is the amount of indicator and the amount of each substance that is being used. For this lab, we decided to use ten drops of cabbage juice indicator and five drops of substance. The manipulated variable are the different substances that we will use, to test their itensities. Finally, the responding variable is the color that would change when a different acid or a base is added to the indicator.
Materials:
Oil: The dense liquid sank to the bottom of the indicator, not changing the color of the indicator a great deal, just making it transparent in certain spots. The substance is therefore neutral.
Windex: The liquid instantly just mixed with the indicator, turning it into quite a bright turqoise blue. This shows that windex is a medium to stronger base.
Wine Vinegar: The liquid turned the indicator a bright, light pink, This would mean that wine vinegar would be a medium acid.
Cedevita: Cedevita turned a very faint pink when mixed with the indicator, which would mean that it is a light acid. What was interesting was that before we mixed the Cedevita, if you looked at the mixture from the side, it had two levels of color, yellow and pink.
Coca Cola: Coke is an extremely light acid, because the red is very faint; it is almost transparent.
Milk: Milk is a very light acid, because the indicator turned into a very light purple. The mixture was also quite cloudy, not as clear, like the others.
Guarana: Guarana is a medium to strong acid, because the color of the indicator turned a very strong pink,
Multivitamin: We got an almost same reaction as we did with the Cedevita- a transparent, light pink.
Green Tea: It was quite surprising for us that the green tea turned into a very faint color of red, meaning that it is a light acid.
Conclusion: To repeat, the guiding question for this lab was "How can you determine the strength of an acid or a base uasing a cabbage indicator?". I believe that my hypothesis was partially correct. The intensity of an acid can be determined by how strong the red/pink color is. The stronger the color is, the intensity, as well as the number on the pH scale will be higher. As for the base, the more intense the blue is, the stronger the base will be, and the lower the number on the pH scale. However, when a neutral substance is added to the indicator, it doesn't turn the indicator red, it just simpy doesn't change it's color at all.
Further Inquiry: During this lab, I believe that there weren't any errors, because it was quite a simple lab, and the only thing we had to look out for was the controled variable (making sure that the exact amount of drops is added to the indicator). However, I do wonder whether the amount of a certain substance will affect the intensity of the color the indicator turns. My opinion, or hypothesis, is that it won't change the indicator much, because the amount of a substance doesn't change it's chemical properties, and doesn't affect it's pH.
Hypothesis: I believe that when the litmus paper is put into an acid, it will turn red, and if it put into a base, it would become blue. The intensity of an acid or a base can be determined by the intensities of the two colors shown on litmus paper. Also, the neutral solution will probably turn green. Some examples of substances that will probably turn out to be acids will be lemon and oranje juice, HCl solution. Some liquids that I am expecting to be bases are most of the cleaning supplies that could be found around the house. Substances that are expected to act very gently, and with little affects, such as baby oil, will probably go green, and turn out to be neutral.
The Variables: The controlled variable of this lab is the amount of indicator and the amount of each substance that is being used. For this lab, we decided to use ten drops of cabbage juice indicator and five drops of substance. The manipulated variable are the different substances that we will use, to test their itensities. Finally, the responding variable is the color that would change when a different acid or a base is added to the indicator.
Materials:
- Cabbage Juice Indicator
- Oil
- Windex
- Wine Vinegar
- Cedevita
- Coca Cola
- Milk
- Guarana
- Multivitamin
- Green Tea
- Pipette
- A test plate
- Cut up the cabbage into small pieces.
- Put the pieces of cabbage into extremely hot water, and let the color of the cabbage dissolve, until the water has turned very dark blue/purple.
- Take the cabbage out of the indicator, and, with a pipette, put 10 drops into the small holes inside the test plate.
- Using a new pipette, put five drops of a wanted substance into one of the holes.
- Observe the change in color, as well as the color's intensity. Write down your observations.
- Repeat the same procedure for every new substance.Remember to use a new pipette for each substance, so that you do not mix the liquids with each other.
Oil: The dense liquid sank to the bottom of the indicator, not changing the color of the indicator a great deal, just making it transparent in certain spots. The substance is therefore neutral.
Windex: The liquid instantly just mixed with the indicator, turning it into quite a bright turqoise blue. This shows that windex is a medium to stronger base.
Wine Vinegar: The liquid turned the indicator a bright, light pink, This would mean that wine vinegar would be a medium acid.
Cedevita: Cedevita turned a very faint pink when mixed with the indicator, which would mean that it is a light acid. What was interesting was that before we mixed the Cedevita, if you looked at the mixture from the side, it had two levels of color, yellow and pink.
Coca Cola: Coke is an extremely light acid, because the red is very faint; it is almost transparent.
Milk: Milk is a very light acid, because the indicator turned into a very light purple. The mixture was also quite cloudy, not as clear, like the others.
Guarana: Guarana is a medium to strong acid, because the color of the indicator turned a very strong pink,
Multivitamin: We got an almost same reaction as we did with the Cedevita- a transparent, light pink.
Green Tea: It was quite surprising for us that the green tea turned into a very faint color of red, meaning that it is a light acid.
Conclusion: To repeat, the guiding question for this lab was "How can you determine the strength of an acid or a base uasing a cabbage indicator?". I believe that my hypothesis was partially correct. The intensity of an acid can be determined by how strong the red/pink color is. The stronger the color is, the intensity, as well as the number on the pH scale will be higher. As for the base, the more intense the blue is, the stronger the base will be, and the lower the number on the pH scale. However, when a neutral substance is added to the indicator, it doesn't turn the indicator red, it just simpy doesn't change it's color at all.
Further Inquiry: During this lab, I believe that there weren't any errors, because it was quite a simple lab, and the only thing we had to look out for was the controled variable (making sure that the exact amount of drops is added to the indicator). However, I do wonder whether the amount of a certain substance will affect the intensity of the color the indicator turns. My opinion, or hypothesis, is that it won't change the indicator much, because the amount of a substance doesn't change it's chemical properties, and doesn't affect it's pH.
