S ScienceFairProjects.info
Easy⏱ time40 min + dry$ cost4

Homemade pH Strips

Soak paper in cabbage dye to make reusable test strips for any liquid you find.

Start building ↓
fig — working model Result first

The build

Step 01

Soak the paper

Steep paper strips in cabbage indicator.

Step 02

Dry them

Hang strips to dry fully.

Step 03

Cut to size

Snip into handy test strips.

Step 04

Test liquids

Dip a strip and read the colour against a chart.

Working Principle

The dried anthocyanin pigment in the paper still changes colour with pH, giving an instant, portable acid–base reading.

The science behind it

A closer look

It's the cabbage indicator in solid form; the colour shift reveals the hydrogen-ion level of whatever you dip it into.

Take it further

Variables to test

  • 1 Build a colour key and test rainwater.
  • 2 Compare your strips to store-bought pH paper.
← Previous
Galvanic Corrosion Race
Next →
Penny Cleaning Chemistry
↑ Back to all Chemistry models

More Chemistry

fig — working model Chemistry

Lemon Battery Array

Wire lemons with zinc and copper electrodes in series to light a real LED from fruit.

Easy⏱25 min$6
fig — working model Chemistry

Reaction Volcano

Baking soda and vinegar erupt on cue while you measure how the ratio changes the blast.

Easy⏱30 min$7
fig — working model Chemistry

Elephant Toothpaste

A catalyst makes hydrogen peroxide erupt in a giant foam column in seconds.

Medium⏱20 min$8