Stained glass can transform transparent windows into art using
colourful glass shapes. In this experiment you can create your own colourful window art using the science of crosslinking.
Equipment:
1 straw
Shallow tray or dish
Cookie cutter
Toothpick
Spatula
Paper towel
Ingredients:
15g gelatin
400ml boiling water
Food colouring
Instructions:
1. Add the gelatin to the boiled water and stir well until dissolved.
2. Pour the water into the tray and allow to set in the fridge for 4 hours.
3. Once set, use a straw to make several holes spaced across the gelatin. Use a toothpick, if necessary, to pull out the gelatin plug left by the straw.
4. Fill each newly created hole with a drop of food colouring. Let the gelatin sit for 4 more hours in the fridge, checking often to watch the food colouring spread.
5. Use cookie cutters to cut shapes out of the gelatin sheet. Carefully remove the shapes from the tray using a spatula.
6. Dab the shapes dry with a paper towel to remove any residual food colouring, then place them on a window, holding each one
for a few seconds until it sticks.
7. Watch the shapes change as the water evaporates over the next few days.
8. When they are dry, peel the shapes off the window and rehydrate by soaking in water for a few hours.
The Science behind the window wobblers:
Window wobblers use gelatin to transform the liquid water into a solid gel.
This gel can still absorb fluid and you
may have noticed the drop of food colouring spread out over time from the hole that was created, moving further into the jelly.
This is due to a process called diffusion, whereby molecules move from areas of high concentration to areas of low concentration.
The high concentration of food colouring spreads out to areas of the gelatin mixture that do not have as much.
Since the window wobbler is mostly made of water, the heat from the sun as the wobbler sits on the window causes the water to evaporate, making it thinner and less flexible.
By dropping the jelly back into water, water can be re-absorbed, enabling the jelly to swell back up to a wobbly state.
The wobbler can then, of course, be stuck onto the window again.
Explore Further:
Can you measure the rate of diffusion of food colouring as it moves away from the hole created by the straw?
Does the rate speed up or slow down over time?
Will the amount of sunshine a wobbler is exposed to change how quickly the water evaporates from it?
Can you measure this difference?
Does the wobbler shape rehydrate better with warm or cold water?
Why do you think this is?
The Kitchen Science Cookbook by Dr Michelle DickinsonThe Kitchen Science Cookbook is about bringing science into the home; making fundamental scientific principles accessible, through experience, and creating memories of discovery and play that will last a lifetime — and hopefully foster a lifelong love of science.
You don’t need any scientific experience and the experiments only require ingredients and equipment found in most homes.
They are also designed to be enjoyed by the whole family so the little ones can be involved to.
Author Dr Michelle Dickinson is a nanotechnologist, researcher and educator, and Member of the New Zealand Order of Merit.The Kitchen Science Cookbook
by Dr Michelle Dickinson
Published by: Nanogirl Labs Limited
RRP: $49.95
