1. An investigative science activity for Year 3 students (working towards VELS Level 3) by Jenny Douglas, Janet Troy and Vanessa Keenan-Boldt G R O W Y O U R O W N C R Y S T A L S

2. I N T R O D U C T I O N Show students a selection of crystals and find out what is already known. Ask questions such as: What is a crystal? What is it made of? How is it formed? Are there different shaped crystals? Pour some sea salt into the palm of your hand and walk around the room allowing students to view it without saying anything. Once all students have observed it, ask the following questions: What do you think the substance in my hand is? Does this salt look different than the salt used in your home? If so, how? Where do you find salt? How is it used? (Most students will say on food or in cooking, but encourage them to think of other uses, eg. on slippery roads, in the ocean / sea, curing meat.) How would you describe salt? (Responses might include shape, colour, odour, etc.) Get students to look at salt using a hand lens and under a microscope and discuss what they see. Is it crystals? Explain that they are going to do an investigation using salt to see if they can grow their own crystals…

3. Science: Science knowledge and understanding VELS Progression Points 2.25: –Awareness of similarities and differences between materials in a group –Knowledge of everyday changes related to matter… Science at work VELS Progression Points 2.25: –Recording of observations made during teacher directed experiments involving measurement in the collection and recording of data –Recognition of simple patterns evident in collected data –Awareness of safety procedures undertaken during experiments V E L S : S C I E N C E

4. English: Writing activity Students write an information report on what happened during their crystal investigation. The structure should include: a title, a general statement, a description of what happened and a conclusion. –VELS Progression Point 2.75: Composition of texts for different purposes; for example, to narrate, inform, describe, present a point of view or explain The Arts: Collage & Watercolour activity Students use a variety of papers, including tissue and tracing paper to create a crystal collage. Watercolour pencils can then be used to add a luminescent effect. –VELS Progression Point 2.25: Experimentation with different combinations of media, materials, equipment, and/or technologies to create arts works that suit a chosen purpose Design, Creativity & Technology: Producing –VELS Progression Point 2.25: With significant teacher direction and assistance, use of a few basic tools, equipment and simple techniques to make a product; eg. preparing and combining familiar materials, ingredients or components V E L S : O T H E R S U B J E C T A R E A S

5. Mathematics: Measuring, graphing & working mathematically Students measure the size of crystals at regular intervals and plot the change in size on a bar graph (also incorporates ICT). Measurement, Chance & Data –VELS Progression Point 2.25: Use of formal units of measurement; for example, metres to measure length, and hour, minute and second for time –VELS Progression Point 2.25: Displays of data as a column or bar graph –VELS Progression Point 2.5: Construction of an appropriately labelled bar graph Working Mathematically –VELS Progression Point 2.25: Use of materials and models to solve problems and explain answers V E L S : O T H E R S U B J E C T A R E A S

6. To see if we can grow our own crystals – is it possible? P U R P O S E

7. That mixing salt and boiling water will result in crystals forming That crystals can be grown in the classroom in a short period of time H Y P O T H E S I S

8. A glass jar A measuring cup 1 cup of boiling water ½ cup of salt A pencil Cotton string A spoon A paperclip Paper towel To add extra variables, we also used: 1 cup of water (room temperature) 1 cup of cold water (refrigerated for 6 hours) Food colouring (for Method 2 only) M A T E R I A L S

9. Tie the paperclip to one end of the cotton string, and the pencil to the other end. Place the pencil on the top of the jar so that the paperclip is just touching the bottom of the jar. Remove from jar and set aside for later. Boil the water. Pour the boiling water into the jar Add the salt very slowly, about 1 tsp at a time, stirring between additions until completely dissolved. When you find that the salt stops dissolving, you have added enough and your mixture is supersaturated. Lower the paperclip and string into the water and rest the pencil across the top of the jar. Cover the jar with the paper towel. Place the jar where it won’t be disturbed for a couple of days. After about 12 hours you should be able to see small crystals forming at the bottom of the jar, on the paperclip and on the string. After 24 hours there will be more crystals. M E T H O D 1

10. Crystals beginning to form on the string in the “boiling” glass. Crystal-like substance forming around the glass at the top of the water – evident on all samples, more so on the “boiling glass”, with the “cold” glass having the least amount. M E T H O D 1 : 1 2 H O U R S L A T E R

11. Crystals formed on string of “boiling” glass. Crystal-like substance more evident on all glasses. Thin crystal formation on “room temperature” and “cold” glasses. M E T H O D 1 : 2 4 H O U R S L A T E R

12. Close up photos : Crystals formed in “boiling” glass M E T H O D 1 : 2 4 H O U R S L A T E R

13. Foggy substance around glass is more pronounced on all samples. Dry part of string has formed thick salty substance on all samples. Tiny square crystals beginning to form on string that is in “cold water” and “room temperature” water samples. M E T H O D 1 : 4 8 H O U R S L A T E R

14. To produce another variable we decided to try our crystal experiment with a food colouring additive. We followed the same method in our previous example and added food colouring to: a) boiling water b) room temperature water c) cold water M E T H O D 2

15. Foggy substance forming around top of glass. Salt at bottom of glass taking on pink colouring. Small vein-like sticks protruding from string. Random lumpy bits floating in glass. RESULTS IN BOILING WATER AFTER 12 HOURS > M E T H O D 2 : 1 2 H O U R S L A T E R Hi Ness: Did you take a photo 24 hours later? Janet

16. Vein-like sticks protruding from string are more prominent. Foggy substance around glass is more pronounced. Dry part of string has formed thick salty substance. Tiny square crystals beginning to form on string that is in water. M E T H O D 2 : 4 8 H O U R S L A T E R RESULTS IN BOILING WATER AFTER 48 HOURS

17. Photo at left shows results in room temperature water after 48 hours. Photo at right shows results in cold temperature water after 48 hours. Both showed little change except for a crusty salt residue around the dry part of the string. The cold water started and remained quite bubbly. M E T H O D 2 : 4 8 H O U R S L A T E R

18. More crystals were formed in the glass of boiling water than any other. Crystals were formed in all samples tested however significantly more crystals developed in the boiling water that had no food colouring. Adding food colouring appeared to decrease the amount of crystals formed in all water temperatures. M O R E R E S U L T S

19. This investigation supported our hypothesis that mixing salt and boiling water will result in crystals forming. Our findings also supported the hypothesis that crystals can be grown in the classroom in a short period of time – within just twelve hours we were able to observe some crystal formation, and after 24 hours the crystals had clearly formed. D I S C U S S I O N

20. C O N C L U S I O N

21. Project Planning Jenny Douglas, Vanessa Keenan-Boldt & Janet Troy Experiment - Method 1 (without food colouring), including written observations and photography Jenny Douglas Experiment - Method 2 (with food colouring), including written observations and photography Vanessa Keenan-Boldt Introduction Activities Janet Troy VELS - Science Vanessa Keenan-Boldt Other Subject Activities & VELS Janet Troy Graphic Design Janet Troy D E L E G A T I O N O F A C T I V I T Y