Making science palatable

'The Kitchen Science Cookbook', by Dr Michelle Dickinson, published by Nanogirls Labs Limited, $50
'The Kitchen Science Cookbook', by Dr Michelle Dickinson, published by Nanogirls Labs Limited, $50
With the school holidays coming to an end, finding things to do can be difficult but Dr Michelle Dickinson has come up with a solution.

She has written The Kitchen Science Cookbook and it's full of easy science experiments - some edible - that will entertain for hours.

Dickinson, aka Nanogirl, is on a mission to make science and engineering accessible to all.

She has a background in biomedical and materials engineering and has combined her interests to give her a unique insight into how nature and technology can learn from each other for scientific developments.

Dickinson is the founder and director of the social enterprise Nanogirl Labs Ltd. She is also an honorary academic in engineering at the University of Auckland, has been awarded a New Zealand Order of Merit and was winner of the Women of Influence award for science and innovation in 2016.

``Using the scientific knowledge I've gathered from my experience in research laboratories, I've spent three years in the kitchen at home, trying different experiments. After lots of trial and error we have come up with the top 50.''

The book is divided into sections on different types of experiments - electricity, motion, pressure, reaction, sound, surfactant, colourful, construction, edible.

She strongly believes everyone should be able to learn about science and how things work.

The ``recipes'' in the book require no previous science experience and use ingredients and equipment commonly available in the home.

She hopes the recipes will help develop science skills in a way that is fun.

``You don't need qualifications to be a scientist - just curiosity, a willingness to try things and to get things wrong from time to time.''

 

PHOTOS: SUPPLIED
PHOTOS: SUPPLIED
Unicorn Noodles

These amazing unicorn noodles will transform from blue to pink as you watch.

Scientific principle
pH (potential of hydrogen)

Time required
15 minutes

Ingredients

red cabbage
lemon
clear noodles (vermicelli or glass noodles work well)
hot water

Equipment

large saucepan
knife
stove
large heatproof bowl
sieve or colander

Instructions

1. Roughly chop the purple cabbage leaves and place in the saucepan.

2. Add enough water to the saucepan to half cover the cabbage leaves.

3. Bring to the boil and cook for 5 minutes on the stove.

4. Place a colander over a large heatproof bowl and strain the hot cabbage.

5. Put the cabbage aside - if you like, you can add a pinch of salt and dash of vinegar to make it into a tasty side dish!

6. Pour the cabbage water back into the pan and add the noodles.

7. Simmer for 5-10 minutes, until the noodles are soft and blue.

8. Use the colander to drain off the water and transfer the noodles to a plate or bowl.

9. Squeeze fresh lemon juice on to the noodles and watch them turn pink!

 

Science behind the unicorn noodles

Purple cabbage is purple due to a pigment called anthocyanin. This same pigment is also found in blueberries. As the cabbage boils, the anthocyanin leaches into the water.

When the dehydrated noodles are added to the cabbage water the anthocyanin is absorbed.

Scientists use a scale called the pH scale to describe the concentration of hydrogen protons in a solution. With 7 being neutral, a pH of less than 7 means the solution is acidic, while a pH greater than 7 means the solution is alkaline. Anthocyanin changes colour depending on the pH of the solution it is exposed to. When it is neutral (or at pH 7) it is purple, but if it comes into contact with something acidic, such as lemon juice, it turns pink. An alkaline solution, on the other hand, would make the anthocyanin turn blue, green or even yellow.

In addition to being a tasty snack, the unicorn noodles are also an edible pH meter!

 

Explore further

What happens when you sprinkle an alkaline material, such as baking soda, on noodles?

Can you estimate the pH value of other household products - such as vinegar or laundry powder - using the leftover cabbage juice?

Using what you know about anthocyanins, can you explain why the blueberries in blueberry muffins sometimes look green around the edges?

 

Candy crystals

Watch in awe as you grow your own edible, crunchy, candy crystals - the longer you leave them, the bigger they grow!

Scientific principle
saturation

Time required
3-7 days

Equipment

wooden skewer
clothes peg
saucepan
tall, narrow, clean glass or jar

Ingredients

1 cup of water
2-3 cups of sugar
food colouring

Instructions

1. Heat the water in a saucepan over a low heat until it is simmering.

2. Slowly add the sugar, stirring constantly, making sure that the sugar dissolves in the water before adding more.

3. Keep adding the sugar until the water starts to look cloudy. This is the point where no more sugar will dissolve.

4. Remove the pan from the heat and allow to cool.

5. Wet the skewers with water, then roll them in the remaining sugar. Leave for a few minutes to dry.

6. Once the sugar solution has cooled, pour into the glass or jar and add food colouring.

7. Clip the clothes peg to the wooden skewer so that the skewer is suspended in the centre of the glass and is approximately 2cm from the bottom of the glass.

8. Leave the glass on a table where it will not be knocked over and watch it grow.

9. The first crystals should form after three days and will continue to grow bigger.

10. You can help your candy crystals to grow by checking for, and removing, any crusty film that forms on the surface of the solution.

11. When you are happy with the size of your candy crystal, remove it from the solution and leave it to dry for a couple of hours before eating.

 

Science behind the rock candy

If you pour a spoonful of sugar into a glass of cold water and stir it, the sugar will dissolve into the water. Eventually, if you keep adding sugar to the water it will stop dissolving. However, if the water is heated, more sugar can be forced to dissolve in the water, creating what is called a super-saturated solution . As the water cools back down, the super-saturated solution becomes unstable since it contains more sugar than it can hold. The sugar then starts to come out of the solution and reforms as solid sugar crystals.

When the sugar starts to come out of the solution it finds the lowest energy surface to form on. As it takes less energy for the sugar crystals to form on top of other crystals than to try and form on their own in the solution the skewers act as seeds for the new sugar crystals to grow. The more the sugar solution cools, the more sugar crystals come out of the solution - and the bigger the candy crystal grows.

 

Explore further

Can you think of ways to flavour your candy crystals with peppermint oil or vanilla essence?

Do you think this will change the structure of your candy crystals?

Can you make crystals with other crystal-forming materials such as salt? Do the crystals look the same or different?

How big can your crystal candy grow? Will it keep growing forever or eventually reach a maximum size? Why do you think that is?

 

Shower cakes

Make bath time much more fun by washing with your personally designed, and scientifically crosslinked, wobbly shower cakes!

Scientific principle
Crosslinking

Time required
30 minutes plus 3 hours setting time

This recipe is not edible

Equipment

Silicone muffin tin or small round plastic container

Ingredients

3g (1 tsp) gelatin
60ml (¼ cup) boiling water
85g (½ cup) bar soap
1 drop food colouring
1 drop olive oil

Instructions

1. Carefully pour the boiling water into a bowl and add the gelatin, stirring until completely dissolved.

2. Add the oil and food colouring.

3. Grate the soap and add to the bowl, stirring gently to mix.

4. Carefully pour the mixture into a silicone muffin tin or plastic container.

5. Refrigerate for 3 hours.

6. Use in your next shower.

7. Store in an airtight container to stop the cake from evaporating.

 

Science behind the shower cakes

Gelatin is made up of coiled up proteins, which are unique because they can be heated up to 100degC without breaking down or denaturing. When gelatin is dissolved in hot water, the protein chains unravel and stretch, floating around in the water. As the water cools, the gelatin strands start to coil again, but they become tangled with other gelatin chains, trapping some of the water inside their coiled structures as they do so, through weak bonds called hydrogen bonds. This process is called crosslinking. The coiling results in the soapy water getting caught in between the molecules so it cannot move freely anymore and the mixture transforms from a liquid to a gel. As you rub the gel on your skin in the shower, the friction or rubbing help to release the soap and water from the gel on to your body.

 

Explore further

What happens when you mix more or less of the gelatin into the hot water? How does the structure of the shower cake change? Why do you think this is?

Can you add other ingredients such as glitter or peppermint oil to your cakes to add some sparkle and scent?

What happens if you don't store your shower cake in an airtight container? Why do you think this happens?


 

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