What's a PH indicator? What does the PH mean?

Question

I'm doing something about a ph indicator with a red cabbage for the science fair but I have no idea what ph is. Please help!

Answer 1

ph is a measure of how acidic or basic something is
the ph scale goes from 1-14

acids have a ph less than 7
bases have a ph higher than 7
7 is neutral, such as water or salts

there are several ph indicators which tell ph. Red cabbage juice is one. For that you will need to either have or look up a color chart which tells what the ph is based on what color the substance turns. There is also litmus paper, which turns either blue or red for base or acid. If you want to be more exact you can use an electronic ph reader.

Answer 2

The lower the pH (power of Hydrogen), the more acidic the substance is. The higher the pH, the more akaline the substance is. As a general rule, the farther the pH gets away from 7.0 in either direction, the more likely it is likely to be involved in a chemical reaction when it comes into contact with other substances:

Sample pHs:

Hydrochloric acid 0.1
Battery Acid 0.5
Cola 2.5
Pure Water 7.0 (neutral)
Sea water 8.0
Household ammonia 11.5
Bleach 12.5

Answer 3

you're measuring the speed of reaction through a pH indicator?a pH indicator measures the acidity or the alkalinity of a substance. i do not think it can measure the speed of reaction. anyway, if you really want to know what the green means, get a pH chart where you can see what each color means. I'm concluding that your substance turned acidic.

Answer 4

A Ph indicator tells you if the substance is an acid or base. Ph stands for portion of hydogen. Low ph means it's acidic, high ph means its a base

Answer 5

pH has to do with testing if a substance is an acid or a base. Where the term acid and base refer to the concentration of hydrogen ions (pH) in the substance; acids have a high concentration of hydrogen ions, while bases have a low concentration of hydrogen ions
Your experiment is to make your own pH indicator from red cabbage, and use it to measure some liquids to see whether they are acids or bases.

Here you could find, how to do it:
http://www.howstuffworks.com/experiment1.htm
http://chemlearn.chem.indiana.edu/demos/RedCabba.htm
http://chemistry.about.com/library/weekly/aa012803a.htm

good luck