Best/Safest Indicator?

[fullsteam]

Hello, I'm new.

I am running a STEM club with a group aged 8-10 years and we are hoping to this experiment from gsk https://www.gskscienceeducation.com/media/412926/Fighting_back_Lab_Infectionindd-1-.pdf#ga-track . I was looking to buy Universal Indicator but it seemed very expensive just for the sake of one session, so started to look for Phenolphthalein. However upon reading the safety sheet I was taken aback by all the warnings! I then noticed the same about the universal indicator. 

I would like to use a liquid rather than indicator strips as I just think the "effect" will be better. But I am concerned about safety issues so can someone please advise which is best from the following:

Phenolphthalein

Universal Indicator solution

Methyl Orange solution?

Note, as you can tell I am NOT a Science teacher! Any suggestions welcomed!

[hypervalent_iodine]

I can't acccess the link you posted.

It's important to consider context and quantities when reading MSDS's. Phenolthalein is perfectly safe for most purposes (you're only uses drops at a time), just don't go drinking it by the cup full or pouring it all over people. I don't know what the experiment is you want to perform, but you may still want to invest in PPE for the kids if you don't have some available. Depends on what you're doing, but at least gloves and safety glasses and some sort of apron or lab coat. That will help mitigate any risk.

[John Cuthber]

For many years, phenolphthalein was used medicinally as a laxative. It was taken off the market because there's a suspicion that it caused cancer in some animal studies.

However, many millions of people swallowed it regularly over a period of many years and the doctors never noticed any raised cancer risk.

So, if one of your class drinks the phenolphthalein they will regret it, but it is unlikely to do them any long term harm.

The other indicators are also generally not very toxic.

However if you want to remove the risk of being "accused" of putting the kids at risk.

http://www.bbc.co.uk/schools/teachers/bang/videos/lesson1_red_cabbage_indicator.shtml

 

Another thing to consider; do any of the local schools support your club?

They might donate a little universal indicator.

 

 

[fullsteam]

Thank you for your replies, to be honest I was mostly concerned about the warnings regarding inhalation.Though as you rightly point out, it will only be a drop or two and I won't be handing over the bottle to any of the children anyway!

It looks like it may be easier to get hold of Methyl Orange - does anyone have any opinions on this as an indicator?

Ah also, you won't be able to access that link above as I think you need to be signed in to the site...the experiment is to show how malaria spreads. I give the kids test tubes at the start of the session, all but one have distilled water in. One has bicarb added, but they don't know which. Each student takes a pipette from someone else's tube and deposits in another. This carries on and at the end I reveal how many were infected at the start...then use the indicator to show who is infected now. Hope this makes sense!

[John Cuthber]

Dilute solutions of bicarb might not be alkaline enough to affect phenolphthalein. Methyl orange might be a better bet. Make sure you do a trial run first or the kids would get a valuable lesson in the fallibility of teachers.

Universal indicator might be interesting- it may give an idea of "how badly infected" someone got.

[hypervalent_iodine]

Neat idea for an experiment. I don't have anything much to add to John Cuther's post. As he says, make sure you test your experiment first. 

[fullsteam]

Thanks so much, yes I was worried it may not be a strong enough solution, for example of someone had only been infected once and had just 3ml of bicarb sol. in their test tube. I will certainly test first.

I loved the idea, gsk education website is fantastic - loads of ideas!