Food and Digestion
Hello again folks,
This week we're talking about food and digestion.
To start off I thoroughly recommend the British Science Association CREST award resources. This pack is for 7-11 year olds, but they have resources for older and younger age groups, Included in here are several great food related activities including making cheese and yoghurt, testing different types of toothpaste, experiments in making tea and jelly setting (you might be surprised what happens when you try to make pineapple jelly). Do try out some of the other investigations too, they're well worth a go.
Now that summer is upon us, why not have a go at making ice cream using salt and ice as a way of cooling it down. If you don't have the ingredients listed here, there are several other ice cream recipes that work too. This method works best for small quantities, for larger quantities you'll need a freezer. If you do have access to a freezer, then this no churn recipe is pretty straightforward.
Red cabbage makes a natural indicator that detects how acidic or alkaline a solution is. Here's a video from the Ri showing you some experiments you can do with it. They use a blender, but I find just soaking chopped up cabbage leaves in boiling water for half an hour works just as well if you haven't got one. If you have any left over cabbage water then soak some sugar paper, filter paper or other fairly absorbent paper in the cabbage water and hang it up to dry. Once dry, try painting vinegar or a bicarb solution on it for cool colour changing effects.
For those of you looking for an engineering challenge, check out Practical Action's Squashed tomato challenge. Can you transport a punnet of strawberries down a mountainside without damaging them? Alternatively have a go at some kitchen chemistry making a biodegradable plastic out of milk or extracting DNA from strawberries.
And finally ...
A couple of food themed science tricks:
The floating teabag trick is one of my favourites to perform and usually gets a nice 'ooooh' from the audience. It does need the right sort of teabag though (usually the ones you get from conferences etc that are wrapped individually). If you can't lay your hands on one, let me know and I'll post you a few (just don't use them for tea as they're probably several years old).
The floating sausage trick is an optical illusion and was originally shown to me in person by James Piercy, who appears here demonstrating it on this video.