Soup in a can – a lesson in exothermic reactions.

Monday, April 13th, 2015 | EMILY HALL | No Comments

A while ago, a friend gave me this can that she had been given as a novelty prize somewhere somehow.

IMG_2357

Anyway, because it was “science-y” she thought I might enjoy it.

I must admit it’s been sitting on the shelf for a wee while. Mostly because every time I look at it and think I should try it out, something else comes along to distract me. Also due to being vegetarian for most of my life, the contents of the can have never really screamed my name. Recently though, I have heard advertisements on the radio for a similar or possibly the same product. I decided to pull out the can and give it a try. I don’t eat meat so I decided to use my carnivorous children as taste testers.

IMG_2359

IMG_2360

 

The can itself feels squishier than a regular can, like it is covered in foam under the label. I think the indicators on ours were not working because, as you can see, although the instructions said they would turn from black to green, both indicators were white initially.

Before we started, I went to the hotcan website to find out what was in there to produce the heat (water and calcium oxide) mostly because I wanted to cut the can apart after the experiment and didn’t want any chemical burn surprises

Pushing in the bottom of the can made a popping noise immediately.

IMG_2361

 

 

 

 

Shake it like a polaroid picture. We shook the can the required amount of time and then set it on the bench as specified in the instructions. Almost immediately, the can began to dance on the kitchen bench and steam was billowing out the bottom. (I told the kids to get back because I actually thought it was going to blow, thankfully this stopped fairly quickly)

After waiting the required time and using the ultra scientific method of feeling the can with our hands (broken indicator, remember?) we decided it was done and had a look/taste.

Reviews of the soup were favourable. The temperature was hotter than expected (said the tasters) there were no chunks, just a smooth soup. Taste was what you would expect from tinned soup. The boys did mention that there was less soup in the can than they had expected. The reason for this became clear when we opened up the can.

IMG_2364Inside the can you can see there is a cylinder coming up through the centre of the can – presumably this is so the soup heats from the middle to the outer layer. The foamy consistency of the can is a layer of insulating foam between the label and the can which would help with the soup heating, staying hot, and not burning your mitts off when you hold the can.

When we took the bottom off we saw this:

IMG_2368

Slightly hard to see from the image but it is like a bladder of what I assumed was water originally surrounded by a chunky white powder.

 

 

 

I asked the children (12 and 11) as I was writing today (2 days later) what if anything they had learned/remembered from this whole experience.

  • Water and calcium oxide produce heat which is transferred to heat the soup. You have to shake it to make it work better
  • When you burst the water packet, the water seeps into the calcium oxide, they must have measured the water and the calcium oxide so it produces only a certain amount of heat

An interesting and easy little experiment!

I found this Limestone Lesson Plan on the Royal Society of Chemistry website and thought it could be paired with the hot can for a great Chemistry lesson. Look at the Chemistry of Limestone lesson (which includes heating the limestone to make calcium oxide and then testing it with water to see the exothermic reaction) and then apply the knowledge to how the hot can product works.

 

 

 

It’s Eureka Time again !

Wednesday, April 8th, 2015 | STEPHEN BRONI | No Comments

Eureka Science Communication Awards 2015

Eureka header_2013Hot off the Press  from Eureka HQ:

2015 EUREKA! Workshops and timetable

After a bit of a hiatus we can now advise the dates and venues for our free regional workshops which will help students prepare for the 2015 Sir Paul Callaghan EUREKA! Awards competitions.
This year the Awards have been increased so that the Premier Award winner will take home a prize of $10,000.  Other prizes have also been adjusted.
We will also offer scholarships on the basis of the relevance of presentations to the 11 Science Challenges identified by the Government.

Entries for the Sir Paul Callaghan EUREKA! Awards must be in by 5 p.m. on Friday 19 June – students should go to the EUREKA! website to register their entries.

It is advisable for students to visit the site and bone up on the entry criteria before submitting their entry to avoid the risk of disappointment if they fail to complete the entry requirements.
In addition they can attend one of the six regional workshops where they get all the information they need, including advice on presentation, research and analysis techniques, which will help them put forward the best entry they can.
Details of the dates and venues of the 6 regional workshops are available from the EUREKA! website
Please note that the Wellington and Hamilton workshops will be held on 18 April so its important that students are advised as soon as possible.
Ministry of Education distributed collateral will be in schools in short order.

If teachers wish to attend the workshops they are very welcome and will be provided with the course materials so they can help their students through the entry process.
A special teachers workshop has been organised by the Canterbury organising committee for 23 April – details on the Eureka website.

The regional competitions will be held in late July (dates and venues still to be finalised).
The National Finals Symposium will be held on 3 September in Wellington and will be followed by the Awards Dinner at Government House hosted by the Governor General, His Excellency the Right Hon Sir Jerry Mateparae.

Plans are afoot to extend the Eureka! programme into intermediate and primary schools so we can build a pathway for children from Year 4 (8 year olds) to become champions for the value of science, technology engineering and mathematics education for the future of New Zealand’s economy, society and environment.

Any questions or comments?  Don’t hesitate to contact

Email: eureka@eureka.org.nz
Francis Wevers
National Convenor
Sir Paul Callaghan EUREKA! Awards Programme

For more details go to: http://eureka.org.nz

For details of the Otago Regional Workshop contact: steve.broni@otago.ac.nz