Students like to do experiments. The idea in this chapter is to expose children towards experimentation they can use to get quantitative data about their environment.
Teachers table as Reagent tables
Teacher’s table could be converted into the reagent table ( the place where reagents are kept in a laboratory). Spread some sheets of newspaper over the table and arrange the reagent bottle in the following order.
This set up help you to monitor the student's group while handling the chemicals and students will make less mistake since the chemicals are arranged in the same sequence in which they would be using it while doing the experiment. Keep a plastic bottle also on the table to empty the BOD bottles after doing the experiment.
Preparation of chemical solutions
Manganese Sulphate solution
Dissolve manganese Sulphate of 48g (MnSO4.4H20)/20g in distilled water, filter the solution and makeup to 100ml. Make sure that the solution should not give a blue colour.
Alkaline iodide sodium solution
Dissolve 50g Sodium Hydroxide 13.5g of Sodium iodide or (70g of potassium hydroxide and 15g Potassium iodide) in distilled water and make it up to 100ml.
Starch indicator
2g of starch and dissolve in 50mL hot distilled water. (Add 0.1g Salicylic acid if you are preserving it)
Phosphoric acid solution (90%)
Sodium Thiosulphate solution
Measure 1.25g of Sodium Thiosulphate (Na2S2O35H20) and dissolve it in distilled water and make up to 100ml. Add 1g Sodium Hydroxide to preserve it.
Student’s tables as experiment tables
Each student team will have to convert one of the desks into the experiment table. They could also cover the top of the desk using newspaper if they want. The water sample will be given to them in paper cups, washing the test tube and syringe and another paper cup for disposing of the wastewater.
Conducting the experiment
Please make sure that all students have observed the video of testing the content of oxygen given below and are familiar with the steps.
The water sample collected from the natural water body (pond, stream etc.) could be provided in a bucket and the boiled water which different student has brought in could be transferred to another bucket. Teacher demonstrates the filling of the bottle with the water sample. Each student team will fill their BOD bottle and wait for their turn to do the experiment.
Now teacher will demonstrate the experiment to the students and will invite different teams to conduct the experiment under her/ his supervision. Each team will move to the reagent table and conduct the experiment by taking the turn. Each team has to show the readings to the teachers and verify it. Before going back to their seats, each group has to empty their BOD bottle and syringes.
Teacher's Corner
Students like to do experiments. The idea in this chapter is to expose children towards experimentation they can use to get quantitative data about their environment.
Teachers table as Reagent tables
Teacher’s table could be converted into the reagent table ( the place where reagents are kept in a laboratory). Spread some sheets of newspaper over the table and arrange the reagent bottle in the following order.
Manganese Sulphate, Starch, Sodium Thiosulphate, Alkaline Potassium Iodide and Phosphoric Acid.
This set up help you to monitor the student's group while handling the chemicals and students will make less mistake since the chemicals are arranged in the same sequence in which they would be using it while doing the experiment. Keep a plastic bottle also on the table to empty the BOD bottles after doing the experiment.
Preparation of chemical solutions
Manganese Sulphate solution
Dissolve manganese Sulphate of 48g (MnSO4.4H20)/20g in distilled water, filter the solution and makeup to 100ml. Make sure that the solution should not give a blue colour.
Alkaline iodide sodium solution
Dissolve 50g Sodium Hydroxide 13.5g of Sodium iodide or (70g of potassium hydroxide and 15g Potassium iodide) in distilled water and make it up to 100ml.
Starch indicator
2g of starch and dissolve in 50mL hot distilled water. (Add 0.1g Salicylic acid if you are preserving it)
Phosphoric acid solution (90%)
Sodium Thiosulphate solution
Measure 1.25g of Sodium Thiosulphate (Na2S2O35H20) and dissolve it in distilled water and make up to 100ml. Add 1g Sodium Hydroxide to preserve it.
Student’s tables as experiment tables
Each student team will have to convert one of the desks into the experiment table. They could also cover the top of the desk using newspaper if they want. The water sample will be given to them in paper cups, washing the test tube and syringe and another paper cup for disposing of the wastewater.
Conducting the experiment
Please make sure that all students have observed the video of testing the content of oxygen given below and are familiar with the steps.
The water sample collected from the natural water body (pond, stream etc.) could be provided in a bucket and the boiled water which different student has brought in could be transferred to another bucket. Teacher demonstrates the filling of the bottle with the water sample. Each student team will fill their BOD bottle and wait for their turn to do the experiment.
Now teacher will demonstrate the experiment to the students and will invite different teams to conduct the experiment under her/ his supervision. Each team will move to the reagent table and conduct the experiment by taking the turn. Each team has to show the readings to the teachers and verify it. Before going back to their seats, each group has to empty their BOD bottle and syringes.
Video: using syringe