Activities to develop learning skills-1

Activities using materials from the kitchen
Aim : Learning concepts in science.
Developing thinking skills

Grade : 11year olds
Materials needed : Turmeric powder; Asafoetida; Salt; Tamarind;Lime juice; Besan Baking soda, rock salt, water. Spoons , beakers, measuring jar, rods for stirring, funnel, filter paper.

A note on these activities:

These activities are designed to stimulate observation, data collection and thinking amongst students. It is aimed at laying a foundation for learning the skill of experimentation.

• To begin with teachers are encouraged to use non-laboratory materials, such as thick sticks from old brooms (instead of glass rods), ice cream cups, old (reuse)plastic cups, plastic ounce-glasses(in place of beakers and measuring jars),tea strainers and plastic funnels (instead of glass funnels). The idea is to get students to think about measurements in an intuitive fashion, to look for ways and means of standardizing measures with ordinary materials. For eg, when the fruit juice cartons say 100ml, do they really hold 100ml or more or less?
• These activities are very simple and designed for ‘active’ participation of students reducing teacher dependency ( but not teacher’s presence and guidance is essential)
• These activities are meant to provide an opportunity to students to ‘think through’(not recall ) their data and arrive at conclusions.
• The role of teachers in an activity-based learning is seen merely as one to ask questions and not provide answers. Even if the child is in difficulty, it is hoped that questions provided can be utilized by teachers to help the child find the way to a solution.

Activity 1:
Learning outcomes to be assessed at the end of the activity

• To learn about the term solution, soluble and insoluble substances
• To learn to read instructions to set up and conduct experiments
• To learn to collect information correctly and accurately from experiments
• To make sense of the information collected through analysis
• To write in one’s own words the entire experiment and the results obtained

Instruction sheet given to students at the beginning of the class
Materials needed and the procedure for carrying out the activity is described below.

Materials needed : Turmeric powder; Asafoetida; Salt; Besan (Powdered gram)Baking soda, rock salt, Tamarind (10gms ;make sure there are no seeds.) Lemon. Water, Spoons, beakers, measuring jar. Rods for stirring, funnel, filter paper.

Make sure that the materials needed for this activity are readily available on your table.

• Procedure 2 is the same for all substances except Tamarind and lemon.
• Carry out the procedure given below with all the materials provided.
• Remember to write down your observations as your perform each activity.
• Use clean and dry beakers ( test tube) for each activity.

Procedure 1 :

1. Take the tamarind and add 10 ml of water to it. Observe. Leave it aside for sometime and continue with the lemon. After that proceed with activities given under procedure 1. When you have finished with all of them, come back to this. Observe. Now shake vigorously. Observe again. Add more water to see what happens. Record
2. Cut the lemon into two. Leave the lemon in a beaker and Add 10 ml of water. Take another lemon and cut it into smaller pieces. Keep it in another beaker and add 10 ml of water. Proceed with other experiments. When you have finished the others then observe And write down your observations.

Procedure 2: The procedure must be carried out with each of the material provided.

• Take a spoon full of the given substance in the beaker and add 10 ml of water. Observe. Shake it if necessary and observe again

From your observations can you find answers to the following questions?

{If necessary feel free to design and carry out more activities . Ask your teachers for more materials or other equipment/ materials for carrying out any other activity in order to find answers to the questions. Explain to your teacher, what you intend to do }

• What did you observe when you added baking soda twater? Why?
• What was the minimum volume of water needed tdissolve a teaspoonful of rock salt?
• Whether in the same volume of water (that was needed tdissolve a teaspoonful of rock salt) could more than a teaspoonful of rock salt be dissolved? How?
• In the activity using tamarind,
• What did you notice at the end of 5 minutes?
• What happened when you shook the beaker vigorously?
• What happened when you added more water?
• What term would you use tdescribe what you have in the beaker – tamarind water; tamarind solution; tamarind mixture? Any other? Why?
• In the activity using lemon, did you get lime juice? Is it right tsay then that lemon dissolves in water?
• Is lemon juice a solution , suspension , mixture or a pure substance?
• What are the differences between a pure substance and a mixture. Give examples from your activity.
• What were the differences noticed in the twbeakers containing lemon pieces? How will you explain your observations?
• Compare the beakers containing salt+water and Soda+water with those containing tamarind+ waterand Turmeric+water :- What is the one difference that is very clearly noticeable?
• Using the materials given can you separate
• Turmeric from water?
• Tamarind from the tamarind extract ( not the solid tamarind that has not dissolved)
• Salt from water?
• Soda from water?
• How many teaspoons of rock salt can be dissolved in 10 ml of water?
• What would happen if 25ml of water were added tthe same amount of tamarind?
• If you observe Besan in water and compare it with turmeric in water, what differences would you observe with reference ttheir capacity tdissolve in water?

Reading material to be given to students after the activity is over:

A note on soluble and insoluble substances :

We see that if some sugar is added to water, it disappears after some time and we see only water. However on tasting this water we would know from the sweet taste that there is sugar present distributed along with water. We therefore no longer have sugar and water separately but we have a solution– A solution of sugar in water. This property of some substances to completely disappear when put into water is called “ dissolving”. Certain substances like sugar, glucose, salt, soda etc dissolve in the liquid water to form a solution.

But not all substances dissolve in water. As you have by now learnt from your activities, some substances partially dissolve in water, example tamarind, Asafoetida etc and some just do not dissolve at all eg. Besan.

Those that dissolve in water are called soluble substances and those that do not are referred to as insoluble substances. Water or any other liquid used to dissolve a substance is called the solvent and substances such as salt, turmeric are called solutes. If a solute completely dissolves in a solvent, then what we get is a ‘solution’, where as if it does not then we get a mixture or a ‘suspension’. What category would you put the lime juice in? Suspension or solution? Do you think when we say soluble, we must use it for only those substances that completely dissolve in (water) a liquid or can it be used for those that dissolve partially?

How many teaspoons of salt can be dissolved in say 25 ml of water? Try to find out. When you find that the salt is no longer dissolving, try stirring it with a rod to see if it dissolves? Heat the solution gently and see what happens? When no more salt can be dissolved in a given quantity of water, then the solution is described as a ‘saturated solution’. Salt water that is capable of dissolving more salt is an unsaturated solution.

So you think the solutions you made during your activity were saturated or unsaturated?
The sugar or salt dissolved in water can be separated because they have not undergone any change in their composition. Dissolution does not change the individual characteristic of the substances. Sugar remains as sugar and water as water.

How about cooking soda in water? Discuss with your teacher and find out.

Your kitchen is a great place to experiment. Cooking is a science and art. Try to find out how many substances found in your kitchen can be dissolved in water? Try the oil. Once you become familiar with the stuff in your kitchen we shall do some more experiments using them.