Riga Pardaugava school
(Latvia)
Liquids.
Dissolving sugar in water
Lesson plan and worksheets
(for transnational meeting in Hungary 09.11-11.11.2015)
Subject : chemistry
Age : 14 years( grade 8)
Time : 40 minutes
Aim: to strengthen students' knowledge of the solutions, depending on solubility of the different conditions
Objectives: to develop the ability to formulate an assumption, to design a plan and carry out the experiment, to display graphically the results of the experiment and draw conclusions.
Background
A solution is a homogeneous mixture of two or more substances. Water is a polar substance and will easily dissolve other polar substances such as sugar. The attraction between sugar and water molecules is rather strong so we can dissolve rather much sugar in water. Intensifying the contact between the molecules serves to increase the dissolving rate of sugar in water.
Activities
-Students activate prior knowledge about sollutions ( using IT)
-Students formulate the hypothesis
-Students design and carry out experiments to determine how different factors such as surface area, temperature and sound waves affect the sugar dissolving (with IT)

- describe an experimental procedure that have been used to dissolve sugar
-put down their observations and conclusions in Google form or presentation.
Materials and equipment :
- sugar (sugar cubs, granulated sugar, powdered sugar), water, beakers, graduated cylinder, scales, electric kettle, thermometer, clock/timer on mobile phones,
•
-Wi- Fi connection, mobile phones/ tablets, worksheets, loudspeakers , mp3,laptop, sensors : Sound Level DT320 ;
Temperature PT-100 -200 to 400 °C DT027 .
Lesson plan:
Time
Teacher’s Activity Student’s Activity
5 min. 1.
Knowledge actualization
The teacher distributes QR codes
The questionnaire has following questions:
Test
1 . Water shell of the Earth is
• Atmosphere
• The hydrosphere
• Lithosphere
2. Water exists in nature in the following states of aggregation
• solid
• Liquid
• Gaseous
• A solid, liquid, gaseous
3. During the transition from
Students use mobile phones or tablets , activate the code and complete the task
Students answer the questions

liquid to solid, the volume of its water
• Decreases
• Increases
• Unchanged
4. The main reserve of fresh water on Earth is in
• seas and oceans
• Rivers and lakes
• Glaciers
• groundwater sources
5. Not applicable to properties of water
• Colorless liquid
• Has the taste
• It does not smell
6. The solution is
• A mixture of chalk and water
• A mixture of sand and water
• A mixture of salt and water
7. The solution is not
• vinegar
• Milk
• Mineral water
Teacher receives students answers in
Google docs
2 .Hypothesis and practical work
Problem formulation:
Today you will be in the role of an engineer at the factory producing soft drinks (beverage industry).
-What is the basis for their production? -What other ingredients are included in their composition?
- What matter is the most dissolved?
Your task is to determine what conditions accelerate the dissolving of sugar in water.
-What are your ideas?
Students answer the questions

5min. Discussion.
We discuss what values are fixed
(constant), which - variable (to change), how to register the data obtained in the experiment of studies, think how to arrange the results in a table.
15 min
3. Practical work
Teacher distributes worksheets
Students discuss their plan in pairs, then in class. Students put forward ideas. In the discussion three factors that affect the rate of dissolution of the sugar in water are considered: particle size, mixing, temperature rise.
Students complete the work in groups .Students split into 3 groups- each group has different worksheet with a task and equipment
Students make their own work plan (procedure) for the implementation
1 st group uses timer on mobile phone
2 nd group uses noise measuring sensors and laptop
3 rd group uses temperature measuring sensors and a laptop
Students distribute the duties in groups
Students conduct their experiment and fulfill the handouts nr1/2/3 in Google docs

10.min
5min.
4.Results and discussion
-What problem should have been solved today?
-Formulate the hypothesis of you research
-Has your hypothesis been proved?
Discussion of Results questions:
1. What happens to the sugar at the time of its dissolution in water?
2. What is the difference between the melt and the solution?
3. How does the particle size influence the speed of dissolution?
4. How sound waves effect the speed of dissolution? Why is that?
5. How the temperature rise affects the dissolving sugar in water? Why?
Reflection.
-If you were responsible for the soft drinks pruduction what would you to do to facilitate the process?
Home task: to create diagramms reflecting the process,that the groups observed during their practical work
Students answer the questions
Students answer the questions
Presentation of the results of group 1using google docs
Presentation of the results of group 2 using google docs
Presentation of the results of group 3 using google docs
Groups give their advise

Activity sheet 1
Solubility time dependence on sugar surface area
Write down the steps of your experiment below
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Write down what in your research will be constant and what will be changed?
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.....................................................
Table Solubility time dependence on sugar surface area
Time
Sugar cube
Granulated sugar
Powdered sugar
Which sugar dissolved faster? Why?

Activity sheet 2
Effect of sound waves on solubility time
Write down the steps of your experiment below

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
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
Write down what in your research will be constant and what will be changed?

.....................................................
Table Effect of sound waves on solubility time
Time
Sound waves
No sound waves

Activity sheet 3
Effect of temperature on solubility time
Write down the steps of your experiment below







Write down what in your research will be constant and what will be changed?

.....................................................
Table Effect of temperature on solubility time
Temperature, o C Time