Sports Day Water Loss and an Iron-Poor School Meal
During a hot sports day at a primary school, Themba (12 years old) plays football for 45 minutes. He drank only 200 ml of water since breakfast. Afterwards he complains of a headache and dizziness, and his urine is dark yellow. His friend Lindiwe eats mostly maize porridge and sweet tea for breakfast and lunch; she often feels tired during games and her palms look pale. The school cook serves one meal: white maize meal, cabbage boiled for 30 minutes, and tea with two spoons of sugar. A parent suggests giving Themba a sugary soft drink and Lindiwe an iron tablet from the clinic. The teacher asks the class to use science ideas, not guesswork, to decide what each learner needs and how the school meal could be improved with foods available: beans, spinach, oranges, eggs and milk.
1. Explain, using body systems and water balance, why Themba's symptoms suggest he needs water rather than a sugary soft drink.
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Themba lost water through sweating during 45 minutes of football. He took in only 200 ml, so his body is short of water. Water is needed in blood and body fluids; when water is low, blood volume falls and blood pressure may drop, causing dizziness and headache. The kidneys save water by making urine more concentrated, which is why it is dark yellow. A sugary soft drink adds sugar but not enough water quickly; it can also make him feel full and may worsen thirst. The best first response is plain water, taken in small sips, and rest in the shade. If he becomes very confused or stops sweating, he needs urgent medical help. The science idea is water balance: output through sweat and urine must be replaced.
2. Lindiwe's tiredness and pale palms suggest iron deficiency. Explain the link between iron, red blood cells and oxygen, and suggest a meal from the available foods that would help her.
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Pale palms and tiredness suggest a shortage of iron. Iron is needed to make haemoglobin in red blood cells, and haemoglobin carries oxygen around the body. With too little iron, fewer healthy red blood cells are made, so muscles get less oxygen and Lindiwe tires quickly. Vitamin C helps the body absorb iron from plant foods. From the list, a good meal would be beans with spinach, followed by an orange. Beans and spinach supply iron; the orange supplies vitamin C. Eggs and milk provide protein but little iron. An iron tablet from the clinic may be needed, but improving the diet is also important. Tea with meals should be avoided because it makes iron harder to absorb.
3. Evaluate the cook's meal of white maize meal, overcooked cabbage and sweet tea. How would you improve it using the foods listed?
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The cook's meal is not well balanced for iron or vitamin C. White maize meal gives energy but has little iron. Cabbage boiled for 30 minutes loses much of its vitamin C, because vitamin C is destroyed by long heating and dissolves in water. Tea contains substances that reduce iron absorption, so drinking tea with the meal makes the iron problem worse. Sugar adds energy but no iron. A better school meal would be maize meal with beans and spinach, plus an orange, and water instead of tea with the meal. Boiling cabbage for a shorter time or steaming it would save vitamin C. This is a judgement based on nutrients, not just on filling learners.