Goriya Roger (SPLICER)

There are a couple of main ways, really. The simplest way is using indicator paper. Litmus paper is a classic one. It turns red for acid and blue for alkali. But universal indicator paper is a bit better. It gives you a whole rainbow of colours. You just match the colour to the chart on the box to find the pH number.

If you need a really proper number, you should use a pH meter. It's a digital gadget with a probe on the end. You dip it in, and the screen tells you the exact pH. So, paper is good for a quick look. The meter is for serious stuff, like at uni or in a lab. Hope that helps you out. Cheers.