Making Indicators

Aim: To make acid-base indicators using everyday substances.

Equipment: 

• Red cabbage
• Tea 
• Beetroot
• Turmeric
• Cranberry juice
• A beaker
• Water
• Tripod
• Bunsen Burner
• Gauze mat

Method:

Task One:

For the Cabbage and Beetroot:  Chop the cabbage into small pieces until you have enough to fill 2 cups. Then place the cabbage in a large beaker and add water to cover the cabbage. After that boil over a Busen burner for at least ten minutes for the colour to leach out of the cabbage. Filter out the plant material to obtain a red-purple-bluish coloured liquid. Now you have to place it in a small beaker and leave it to one side, repeat these steps with the beetroot. 

For the tea: Put 100ml of water into a beaker and boil, turn off the bunsen burner and put three tea bags in the beaker. Then remove the tea bags when the tea is very strong. Once that is done place it in a small beaker and leave it to one side.

For the Cranberry Juice: Pour into a beaker and leave to one side. 

For the Turmeric: Mix 1 teaspoon turmeric in 100mL cup of alcohol. Then place it in a small beaker and leave to one side. 

Task Two:

1. You now have five beakers, each containing a different indicator. 
2. Using a pipette, place 5 mL of the cabbage indicator into two test tubes.
3. Add 5 mL of HCI (Acid) to one test tube and 5 mL of NaOH (Alkali) to the other test tube.
4. Record the changes in the table below.
5. Clean the test tubes and repeat for the Beetroot, Tea, Cranberry and Turmeric indicators. 

Results:

 

Indicator	Colour in HCI (Acid)	Colour in NaOH (Akili)
Cranberry	Pink	Green
Beetroot	Red	Yellow
Turmeric	Yellow	Orange
Cabbage	Pink	Green
Tea	Orange	Brown

Discussion: When we were making the indicator, we did not do task 1 because we were not in the science room, so it means there will be no gas to plug in the bunsen burner. However, we just did task two. At first, we put a little bit of acid for the cranberry. I thought that the colour did not change when we put the acid because it was that still the same colour. After we put in some acids we then move to Akili. While we were pouring a little bit of NaOH in the Cranberry it has turned to colour green. We all did the same thing with the Beetroot, Turmeric, cabbage and tea entirely of them had a different colour for the Acid and Akili. You can see that by the table above the I have made to show you guys the results.

Conclusion: I really have enjoyed doing that experiment because it's just really entertaining to watch the change in a different colour. I am looking more forward to the next science we have for the next experiment.