Paignton Library STEM Group

pH

Digital pH Tester

I recently ordered a digital pH meter to go with some of the Chemistry resources at the STEM event and at home.

This is a nice little unit, using 2x LR44 (AG13) cell batteries, I did a quick test on some tap water and some vinegar and got expected results. Seems tap water is slightly on the acidic side, so i may have to do proper experimentation with this.

Easy to set, just add batteries, take off protective cover and place in the liquid that you want to test.

One comment that the instructions are in Chinese, which isn't really helpful, but the unit is easy to use, with some common sense and problem-solving skills.

Measurements are from pH 0 to pH 14, with increments of 0.01 so it should be possible to measure very small changes or gradual changes that may take place during reactions for example.

I will be using this at a future STEM group meeting in the meantime, there is an experiment I want to undertake anyway and this will be ideal.

Tags

#Science,#Chemistry,#pH,#Tester.

#PaigntonLibraryStemGroup,#Science.#Technology,#Engineering,#Mathematics

Red Cabbage indicator

The red cabbage indicator that I am using works fine. However it looks rather red, further investigation and starting discussion on Science Forums about this, suggested a cause and solution.

In essence the indicator is acidic, hence the read colour rather than the purple neutral colour.

I have now made up a new batch, which looks a lot better

new batch of indicator

The image above illustrates the old indicator on the right hand side, the new is in the beaker on the left. You can see quite a big difference in colour.

I have extracted the pH colour scale from the original infographic below

pH Scale

Video

There is a 3 min Video here that I made while making the new batch of indicator up.

Discussion

Tags

#Chemistry,#HomeChemistry,#HomeChemistry15,#Science, #RedCabbageIndicator,#pH,#Scale,#Acid,#Alkali,#Neutral,#Color,#Scale

#PaigntonLibraryStemGroup,#Science.#Technology,#Engineering,#Mathematics