Dyeing 4
Activity: Flower power - Level 3
Achievement Objectives - Whāinga Paetae: Te Weu
3.1 (ii) Identify and compare permanent changes and temporary changes of selected substances. Te Marautanga o Aotearoa: (p.100) Ō Kawekawe, Ngā Āhutanga me ngā Panoni Matū. 1(ii).
Learning Outcome
I will be able to:
- make a solution from flower petals
- change the colour of my flower petal solution by adding either lemon juice or baking soda
- change the colour of my flower petal solution back to its original colour by adding either lemon juice or baking soda.
Success criteria
| Success criteria | Self-assessment | Peer assessment | Teacher assessment | ||||||
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| I can make a solution from flower petals. | |||||||||
| I can change the colour of my flower petal solution by adding either lemon juice or baking soda. | |||||||||
| I can change the colour of my flower petal solution back to its original colour by adding either lemon juice or baking soda. | |||||||||
The juice from most flower petals will change colour in an acid. In this investigation you will find out which flowers are the best at changing colour when mixed with either an acid or baking soda.
Equipment
- Flowers
- Plastic zip lock bags
- White plastic ice cube tray
- Dropper made from a short piece of drinking straw with Blu-Tack pushed in one end
- Lemon juice
- Baking soda
Method
- Collect a range of at least three different flowers. Avoid mixing the flowers.
- Choose one type of flower. Take off the petals of your selected flower and put them into a plastic zip lock bag.
- Add about a tablespoon of water to your petals. Be careful! Don’t add too much. This solution must be concentrated. Crush the petals inside the bag until the water changes colour.
- Use a teaspoon or a dropper made from a straw to transfer about five drops of your petal water into another section of the ice cube tray.
- Add a drop of lemon juice to the four drops of petal water. This is the colour of petal water when acid is added. Write down the colour change in the table below.
- Transfer four drops of your petal water into another section of the ice cube tray. Add a few grains of baking soda and write down the colour change in the table below. This is the colour when a base is added.
- Repeat this experiment again for each of the different flowers to see which flower is the best at changing colour when mixed with acid.
| Colour of flower | Colour of petal water when lemon juice was added | Colour of petal water when baking soda was added |
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- Which colour of flower produced the best colour change when an acid was added?
- Is the colour change of the petal water permanent or temporary? How could you test your answer?
Where to next?
Some flowers change colour depending on the type of soil they are grown in. Hydrangea flowers are commonly grown in gardens. Find out about different colours of hydrangea flowers. Which types of soil change their colour? Which of these soils are acid, base or neutral?