Dissolving candy canes

We're close enough to Christmas now that I've decided one very excited 4 year old and his slightly bemused brother (who is almost 2 and therefore doesn't really understand what Christmas involves) can have fun with some Christmas-themed activities.  The Christmas stickers we've got have candy canes, and my eldest asked me what they were, so I bought a pack.  Then when I thought about it I realised that him eating 10 candy canes over the next month isn't a great idea so I should come up with some alternative activities for some of them!

Warm and cold water plus candy canes

This is a really simple activity, but proved fun (and involved some science conversation) and my son didn't object to there being 2 fewer candy canes at the end!  The aim was to talk about things dissolving, and to see the effect of temperature on the rate at which the candy canes dissolved.

Measuring the water temperature

Back in May, I introduced my eldest to the idea of measuring temperature with a thermometer.  We could have done this activity without one, but I thought it was a good opportunity to use a thermometer again.  I set out two beakers of water (any kind of cup would do, preferably two the same and transparent makes it easier to see what's happening), one tap-cold and one warmed.  I gave my son the thermometer and asked him what we use it for, and he said "for seeing how hot or cold something is" - we've not used one since we made a solar oven in the summer, so I was pleased he remembered.  I asked him to feel the water temperature, and then measure it with the thermometer.  We watched the red line move and stop, and I helped him read off the first temperature (13 degrees Celsius) and he did the second himself (40 degrees).  I like the idea that he feels it first because it helps to give him a firmer idea of what the numbers mean if he sees another similar temperature.  

Candy canes in water

I then asked him what he thought would happen if he put a candy cane in each beaker.  He wanted to know what they are made of, so I said mostly sugar and he told me correctly that they'd dissolve.  We've talked before about how dissolving isn't really disappearing and that the thing that dissolves is still there - we've previously dissolved salt in water and then seen what happens when the water evaporates and it's still there (although I never got round to blogging about it).  I asked whether the hot or cold water would dissolve the candy cane fastest, and he wasn't sure, so he put a cane in each beaker to find out...  

Thinner candy cane in the warmer water

To start with, a bit of pink colour appeared in the water with a little more in the warmer water, but it wasn't fast enough to sit and watch!  We left it for 5 minutes and came back, and when my son lifted the canes out, both were dissolving where they were in the water, and the cane in the warmer water was noticeably thinner!  He took them out and had a good look, then I asked him to have a smell of the water.  He couldn't name the smell, but I explained that it was peppermint, and he tried a bit of one of the other candy canes and decided he liked peppermint...!  

The one in the warmer water is gone!

A further 5 minutes later, and the cane in the warmer water had become thin enough that it collapsed and the handle disappeared into the water too.  My son thought this was amusing, and he kept checking back to see when the other one had gone too (about 5 minutes later).  The nice thing about dissolving the candy cane rather than a sugar cube or salt was that the red colour was visible in the water, so it was obvious that the cane had gone into the water rather than actually disappearing!  I tried to explain that the little bits of water called molecules moved faster when they were warm, and this was why the sugar dissolved faster, but if I'm honest it wasn't a very compelling explanation and I doubt it made much sense, but at least he's had the experience of seeing what happens even if it's not easy to explain why.