KS3 Science Revision

Acids and alkalis are mearsured on the Ph scale. 1 being very acidic and 14 being very alkalic. 7 is neutral (water). Acids and Alkalis are also mearsured in colour, red being acid, blue being an alkali and green being neutral. 1-3 is very acidic and 4-6 is slightly acidic. 8-10 is slightly alkalic and 11-14 is very alkalic. A substance can be tested to see if it is acidic using a universal indicator. Litmus paper is one. It turns red, blue or green depending on the substance. However is doesn't spesify how acidic something is. Universal indicator solution does though. It is a mixture of dyes and can be a whole range of colours which indicate whether something is an acid or alkali.