Monika KapusiEileen Gomes

GROUP: TGroup 15

General IntroductionVELS level: 3Strand: Discipline-based LearningDomain: ScienceDimension: Science knowledge and

Understanding, Science at Work

General Introduction cont.At Level 3, students classify a range of materials such as

solids, liquids and gases according to observable properties, and demonstrate understanding that this system of classification of substances is sometimes problematic. Students describe examples of reversible and non-reversible changes in substances.

At Level 3, students plan, design, conduct and report collaboratively on experiments related to their questions about living and non-living things and events. They select and use simple measuring equipment, use a range of appropriate methods to record observations, and comment on trends. They describe the concept of a fair test and identify the variables associated with an experiment. They develop fair tests to make comparisons and explain how they have controlled experimental variables.

Students describe safety requirements and procedures associated with experiments. They explain how scientific knowledge is used, or could be used, to solve a social issue or problem. They describe aspects of the work of scientists and how this has contributed to science knowledge.

Purpose of ExperimentThe purpose of this experiment is to

observe a saturated solution of sugar and water (plain and coloured), and record the rate and growth of crystallization onto a string at room temperature.

HypothesisSugar crystals will form in both

experiments (in plain and coloured water) within 24 hrs. Sugar crystals will form along the submerged string, and grow into a large rock candy.

Materials Used2-3 cups sugar1 cup boiling waterGlass Jar String (≈13-18 cm)Pencil/ wooden stick Food colouring (Blue)Paper clip

MethodTie string on the middle of a pencil/ wooden stickOn the other end of the string, attach the paper clipBoil 1 cup of water on the stove and keep on low

heatSlowly stir in the 2-3 cups of sugar in the water one

spoon at a time; the solution is ready when no more sugar will dissolve into the water (you’ll see sugar collecting at the bottom of the pan)

Pour the solution into the jarPut the string on top of the jar and let the paper

clip enter the water without touching the bottomStore in a dry, cool place; undisturbedTo keep dust out, place a paper towel over the top

of jar

Method contd.

Results (Student A: clear solution)(Teacher’s Notes: Encourage students to use

varying lengths of string and different jar sizes to see how one relates to the other.)

Length of String: 18 cm Submerged length of string: 8 cmHeight of Jar: 13 cmLength of experiment: 7 days

Day 1Observations: The liquid is a thick syrupy

solution. No crystals formed.

Measurements: 0 cm

Day 2Observations: Top of solution formed a solid

crystal (≈0.5 cm thick); crystal forming along string like a spindle.

Measurements: Crystal is too fragile for external measurements. It appears to be approx. 3 cm in length and 0.5 cm in width.

Day 3-4Observations: Distinct crystals forming

along entire length of string. Measurements:

Length: 4.5 cm Width: 1.0 cm

Day 5-6Observations: Sugar crystal expanding in

width. Bottom of jar has thicker crystal forming than the top portion of the string.

Measurements: Length: 5 cmWidth: 1.3 cm at top 1.7 cm at bottom

Day 7Observations: Crystal has completely

covered entire length of string and paperclip. Because the bottom has a greater width than the top, it has grown into a “boot” shape.

Day 7 cont.Measurements: Length: 7cmWidth at top: 2 cmWidth at bottom: 3 cm

Results(Student B: Blue solution)

DAY 1

ObservationsSee through the jar perfectly. No crystals formed. Water slowly turning into thick syrup.

Measurements0 cm

Blue solution cont. DAY 2-3

ObservationsCannot see through the jar. All of paper clip covered with crystals. Crystals slowly forming on string. Water is still thick syrup. Crystals begin to turn blue in colour.

MeasurementLENGTH: 2.75 -4 cmWIDTH: 2 - 3.5 cm (NOT including the crystals on the string)

Blue Solution cont. DAY 4-5

ObservationsCannot see through the jar. Crystals growing bigger width ways. All of the crystals blue in colour, on paper clip and string.

MeasurementLENGTH: 4.5 - 4.75 cmWIDTH: 4.5 - 5.5 cm (including the crystals on the string)

Blue Solution cont. DAY 6-7

ObservationsCrystals have completely covered the paper clip and have climbed a quarter way up the string. Growing both length and width ways. Majority of the crystals are on the left end of the paper clip.

MeasurementLENGTH: 5 cmWIDTH: 6.25 - 7 cm (including the crystals on the string

DiscussionThe process of growing crystals as a science

experiment was a great success! After following and understanding the directions correctly, the sugar crystals started forming on day 2. Our hypothesis was correct in a sense that we needed a full 24 hrs before the crystallization occurred; we didn’t see any formation prior to day 2. Also, crystallization only occurred on the portion of the string that was submerged in the syrup. The longer the string in the solution, the larger the crystal grew. Food colouring didn’t alter the experiment in any way. The blue crystal and the clear one grew at fairly similar rates.

Kids can experiment with all string lengths, jar sizes, and food colourings to make their sugar crystals.

Errors/LimitationsWe experienced a problem when we first started the

experiment. We had boiled the water first, placed it in the jar, and then slowly stirred in the sugar. At that point the water was already starting to cool, which didn’t allow the sugar to dissolve. After two days, we still didn’t have a crystal grown on the paper clip. After discussing our problem, we realized that the water needed to be warn while the sugar was stirred in. When this stage was finally perfected, the sugar began to cool within the water and crystallize.

ConclusionIn conclusion we learned that when growing sugar

crystals, it is essential to have the sugar dissolved over low heat as you can dissolve more sugar in the water.

Once the ideal environment is created (that is the saturated solution of sugar, room temperature and proper length of string), sugar crystals will grow at the constant rate.

Delegation of ExperimentWe both chose to do the experiment ourselves for

the duration of a week. We also decided to divide the experiment, where one of us chose to grow a clear crystal and the other a coloured crystal so that we can compare and contrast our findings. We decided to demonstrate both options so we can see which one gave more scientific feedback. In conclusion, both experiments were successfully done which confirms that they are both suitable for science experiments in the level 3 classroom.

We distributed our work by creating spreadsheets to tally our data and findings on the daily base, measured our crystals daily and then collect data to compare our observations. We wrote the final copy of the experiment together, and then arranged it on power point.

Teacher’s NotesThis experiment is done best at home with

parental supervision during the dissolving process.

This is a great project to introduce kids to the 3 states of matter (solid, liquid and gas)

Vocabulary to explore: scientific process, hypothesis, saturation, crystallization, solution, dissolve, solid/liquid/gas