Science Project

Can we use cabbages to find out pH?

Shakila Monsur Science project

Index

Why does this work?

Steps

pH diagram

Results

Video

How does this work?

Red cabbage gets its colour from compounds called anthocyanins in its leaves. These anthocyanins are peculiar in that they’re pH-sensitive, and this allows them to be used as pH indicators. If they are extracted from the red cabbage leaves by boiling the cabbage in water, the resulting solution can be added to different substances to test them.

1.Chop the cabbage into small pieces and place the cabbage in a large beaker or other glass container and add boiling water to cover the cabbage. Allow at least 10 minutes for the color to leach out of the cabbage. 2.Filter out the plant material to obtain a red-purple-bluish colored liquid. This liquid is at about pH 7. The exact color you get depends on the pH of the water. 3.Add various household solutions to your indicator and watch it change color.

Add titl

Side note; the colour the dye turns out to be can also show the pH of the water in which this case seems to be around 7 or 8

indicator strips made by soaking paper in the cabbage solution

Bleach

Whaat does tha colour change tell us?

Once the pH indicater (cabbage juice) was added to the bleach, the bleach turned a yellow colour, indicating it is an alkali at around 12 or 13 pH

Orange Juice

What does the colour change tell us?

Once the indicater is added to the orange juice, the orange juice turns a reddish-pink, showing it is acidic at around 2 to 3 pH

lemen Juice

What does the colour change tell us?

Lemen juice was put on a brush then spread on the paper, which turned pink. We can deduct from this that the lemon juice is acidic, with a pH of 3

Thank you!