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

• Solomi PH Tester

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.

Updated 6/8/2023

Now that I have a new batch of Red Cabbage indicator. I would like to investigate some of the chemistry of a recently collected sample of seawater, specifically the following:-

• The pH of seawater.
  
  • Video
• If adding eggshells changes the pH.

Background to this

Eggshell, contains Calcium Carbonate $\ce{CaCO3}$ when added to vinegar $\ce{CH3COOH}$ the pH value increases.

Related information

• Chemistry of egg and eggshells

Adding eggshell to vinegar increases the pH of the vinegar. I will write up my experiment / results and share this. What I want to know is can eggshell do the same to seawater.

This may be a possible solution to ocean acidification.

Links

• Science Forums

Write-up

You can find my write up for this experiment in PDF here. You may want to right click and download, otherwise it will probably just open in a browser. Provided as-is, but it should cover what I did, my results and conclusion.

Tags

#Chemistry,#HomeChemistry,#HomeChemistry16,#Science,#Seawater,#pH,#Investigation

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

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

Video

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

• Add hot water to beaker
• Add red cabbage to water
• Mix (until water is the required purple colour)
• All to cool
• Add to regent bottle

Created more indicator as required.

Discussion

• Science Forum, discussion

Tags

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