Here’s how you can make a tasty sorbet in five minutes while learning about the effect of freezing point depression with ice and salt.
C(9) found the experiment in our Science Experiments book. We had all the supplies so we were ready for some spontaneous learning fun!
What You Need
- Orange juice (or other juice)
- Crushed ice (or snow)
- Salt (about 4 tablespoons)
- 2 ziplock bags, one larger than the other
- warm gloves
What You Do
1. Pour orange juice into the smaller ziplock bag. Squeeze out excess air and seal.
What Happens
The orange juice gradually solidifies and turns into sorbet!
The Scientific Explanation
Adding an impurity (salt) to ice lowers its freezing point. The ice wants to melt back to water, but to do this it needs to absorb heat from somewhere – in this case, the orange juice. Heat is transferred from the orange juice to the ice, freezing the orange juice.
This is an endothermic process (heat is absorbed).
For a detailed molecular explanation of why salt melts ice, see this article.
What We Might Try Next Time
We ended up with a very healthy snack, but for a treat we might make a sweeter sorbet by adding sugar. (Here are the ingredients for a simple lemon sorbet, and a whole list of delicious sorbets here – courgette (zucchini) sorbet looks interesting!) We might even try making ice cream in a bag.
Further Resources
An “Ice Energy” lesson plan (includes ice cream recipes)
Science Experiments: Loads of Explosively Fun Experiments You Can Do
For more hands-on learning fun, head over to Hobbies & Handicrafts at Highhill Homeschool, Homeschool Review at Hammock Tracks, and Science Sunday at Adventures in Mommydom.
We’ve made ice-cream in a bag before – it’s a bit soft but very tasty. And it’s an interesting process to watch. The children love it – what’s not to love with food involved! I love how you write your science posts- very methodical!!
Thank you! With the low gluten and sugar diet around here, taste standards are pretty low – I’m sure tasty soft ice cream will go down VERY well! 😀
Love this experiment, and your clear instructions! I’m bookmarking this yet again. 🙂 Experiments that involve food are my favourite type of learning. 🙂 Thank you for sharing.
Thank you very much! I can’t believe all the years I studied science at school with no edible treats at all that I recall!
Yum!
It was – what is it about freezing things that makes them more fun?!
I love this! Yes, you should try ice cream in a bag. It is so good and fun.
Thanks, Phyllis! I’ve just found your Secret Formula: Ice Cream post. Love the way you set it out as a story. I’ll be coming back to it for sure!
We tried ice cream in a bag, but it didn’t end up working. I need to try it again, and this time have them wear gloves like you did.
Thanks for the pin, Ticia. I nearly listed the gloves as optional, but after reading about the science of this (how cold it gets) I realised that to give the mixture a proper squishing you really need them if you’re going to avoid frostbite!
Hi,
I got so into reading your post I forgot how I found you. Then I went back to my email and realized that you posted a comment on a blog I write for Family and Faith Matters – about the dinner conversation book.
Great posts – so interesting I want to come and be in your classroom.
Many blessings,
Janis http://www.janiscox.com Author of Tadeo Turtle
I also blog at Under the Cover of Prayer.
LOL, Janis – I do that too! Thank you for stopping by to say hello! Lucinda
Edible science is the best! LOL Now, we haven’t done the ice cream/sorbet in a bag, but we’ve made ice cream with (clean) snow and ice cream in an ice cream ball. Lots of fun!
Ooh yes ice cream snow is on my list too! I’ll have to look up ice cream in an ice cream ball – did you post about it? Thanks for stopping by, Jessy. 🙂
Lucinda
Greate science experiment! Popping over from hobbies and handicrafts
Thank you for stopping by! Lucinda
My son has been freezing everything and calling it his desert. Frozen banana in the peel, a cup of lemon juice and water, tomato……. With this experiment he could watch things freeze. Thanks for linking with Hobbies and Handicrafts.
Sounds like great edible science! My daughter’s favourite is frozen goats’ milk. Doesn’t appeal one bit to me but she insists it’s delicious!
This was very helpful and cool thank you!