Dropper bottles

[Ocker]

We always have a problem with kids putting wrong droppers back in bottles when doing precipitation reaction prac exams, even after colour coding droppers and bottles.
It seems once they start a prac exam everything they have been taught goes out the window. however modern eyedrops always come in squeeze bottles with pin hole in top, does anyone know where I could source these bottles
Graeme

[lizzieb]

Hi Graeme,

Perhaps you mean the white plastic type with a 'stull' cap?

SSA and Haines have them. 2 sizes. Cap available separately. SSA a bit cheaper.

Cheers

[Sassi]

Hello,

When I started at this school all dropper bottles were the squeeze bottle type, I dont know how long we have had them for, but since I started (sept) I have had to replace all with 'normal' dropper bottles becasue the bottle cracked and were leaking or the actual lid broke. So I HATE them with a passion, and would not recommend getting them. Although, as I said, I dont know how long they had had these bottles before I showed up....

[Ross]

Graeme,

We use plastic droppers. What you have is a plastic bottle with a plastic "Stull" cap. To open up the dropper, just twist the top part of the cap.

These are both good and bad. The good is you dont get the kids placing the wrong droppers back into the bottles and the bad is they seem to leak and drip a bit and after a while the top disintergrates because of UV exposure.

The easy answer is there is not a good solution to the problem.

Quite a few distributors sell them - Seratta, Hanes, Science Supply etc.

Good luck in finding a good answer to this problem, let me know how you go.

Cheers
Ross

[smiley]

I use stuhl bottles for all the chemicals for my precipation, redox etc pracs. Yes, you do have to replace the lids more than the bottles, but I've had my bottles for a couople of years now, without any deterioration. Maybe yours were ages old, Sassi? I only have Silver Nitrate, KMnO4, and a couople of others still in glass. Usually just the things that need amber glass.

Cheers, K

[estelle]

I don't think it matters what type of bottle or droppers you send chemicals out in they will nearly always come back mixed up. I think they just like to see what new mixtures they can come up with.
I now also try to keep a different set for the seniors expecially with indicators, I recently had the senior chem class come and show me that one of the fish tanks water was so acid that I thought I would find the fish peeling. Lucky I checked before I started to adjust the pH, my reading was alkaline. couldn't figure it out until I had a look at the contents of the senior universal indicator, it was orange. I had sent those bottles out to the year 9 class with some Hcl bottles, needless to say they obviously had a good time mixing up the contents.
I have given up and just send the least amount of chemical in each bottle out and basically have to rinse and refill for the next class. Takes a bit more time but takes the stress out of it.
Estelle.

[lada]

I, too have tried those plastic bottles, but gave up very quickly.
They leaked and I found the twist on the top of lid was a challenge for students. It twists in the same direction as the lids, so kids thought they were opening the top and in fact they opened the bottle and emtied the content in the process.
Lada

[Lis]

I have changed from glass dropper bottles to the stull bottles, I have found them convenient, and easier to use, less mess, but I can see the probs others have talked about. I too have chems like KMNo4, iodine etc in amber glass, does anyone have a trick they use to stop the rubber teat in the bottle from perishing, or going hard?
Lisa

[kimmy]

I have changed most of ours over to the plastic squirt type of bottle. Less damage to the soloutions I have found. Still use amber glass bottles for some solutions. To stop the rubber from going hard on the lid I smear a very small amount of potroleum Jelly on the plastic - seems to work.
Some how though kids and some science teachers still manage to mess up our bottles. As others have mentioned I am sure that they just like to see what they can do.
Some days im sure it is lets see what we can do to send the lab assistant a bit more crazy . It is normally on Friday.
Have a good weekend everyone.
KIMMY

[RosalieM]

I too have chems like KMNo4, iodine etc in amber glass, does anyone have a trick they use to stop the rubber teat in the bottle from perishing, or going hard?
Lisa

I use the dropper bottle caps available from Serrata (discovered thanks to someone else on this website) and just put the droppers in when they go out for classes. That way the rubber doesn't perish. I currently have them on the ones that stain the glass tubes or damage the rubber but I am slowly doing it for all the dropper bottles. I'm still undecided if it is a good idea or not to do it for all of them because of the extra work of washing up the droppers each time, but we'll see how it goes.

[Ocker]

Thank'severyone have 250 Stulle bottles on order.
Will trial them for Yr 12 Prac.exam.
I'm concerned about Lada's comment about tops freezing and having whole top screw off,
as I asaid before as soon as kids go into exam they leave their brains in the bag.
Maybe if I wrap plummers teflon tape around top thread that will prevent this.
Anyhow They are under trial
Let you know after week 8
Ocker

[lada]

Let us know, ocker.
We have the most spoilt kids here at school , they always leave their brains behind, because people like me or some teacher do it ALL for them.
They even asked me how to open the bottles. It only goes one way,
Lada

[pkij]

We use the stuhl plastic bottles here and the glass amber/clear dropper bottles for any chemicals not suited to plastic stuhl bottles. The droppers can leak sometimes but I ask the teachers to let me know if they have problems, and you can buy replacement caps pkt 10 for around $5.00 from Serrata. I think they are safer as the students do not have to unscrew the caps off and they are not breakable glass. We have not had any problems as far as I know with students not being able to use the twist dropper. I check the bottles for deterioration each time they are used and replace as needed, but they seem to last for ages and they are cheap enough if they have to be replaced. They are the way to go I reckon

[Ocker]

Hey Pkij
Besides the obvious, Silver Nitrate Pot. Permanganate & Iodine what other stuff reacts with plastic bottles,
I don't want to re-invent the wheel
Thanks Ocker

[Ocker]

Got the sthul dropper bottles labeled and filled then did trial.
The teacher could not undo screwed whole top off, so I went along and tightened every top and uopened dropper top and tested each one some you just touch and they squirt ( often at an oblique angle ), adjust back slightly and nothing comes out, while others required quit a squeeze to get a drop.
So they are not fool proof, and it was decided kids needed familarisation prac. to use them without being under exam stress.
I think I will continue to change over most of droppers even if just because they bounce when dropped.

[sunray18]

I think that NO matter WHAT we do to try to overcome this problem - the kids will always work out ways to mix things up - nature of the 'beast' perhaps!
What infuriates ME - is when the TEACHERS mix them up!!!