Letters - June 15 2011
How can we use solar energy for our domestic needs?
Dr. K. Ahluwalia
Dear Doctor Sahib,
From drying clothes to making food, solar energy has a wide array of uses in any household. It can keep the house well-lit and warm. Solar hot water tanks and solar boilers can be used to heat water as well as store it for bathing, washing dishes, etc. Solar energy can also be converted into electricity using solar panels. It can power the entire house, or used as a backup in case of an outage. A very simple yet innovative way to save electricity is passive solar heating. But your house needs to be designed in a way that it effectively utilises solar power.
The WHO–recommended process involves exposing water-filled bottles to sunlight for some hours – duration depends on the weather and climate of the region. In developing countries, this method has been adopted by over two million people!
Why is it important to be hydrated. Especially during summers? Can you please tell me what is the best way to go about it?
Dehydration refers to the excessive loss of water and bodily fluids which can cause anything from headaches, muscle cramps, unconsciousness to even death in extreme cases. Like any machine, our body needs constant dose of fluids to keep it cool so that it runs smoothly. Even a small drop in the water level in the body can cause a substantial decrease in performance and bodily fatigue.
Water is also essential for producing sweat which helps in moderating the body temperature. As you know from experience, we sweat much more in summers than other seasons. Hence, it is necessary to constantly consume water so that the body can produce sweat.
Proper caution can easily prevent dehydration. During summers, try and stay indoors in the afternoons – delay your activities till the evening if possible. However, in case they are unavoidable, it is advised that you carry a lot of water and/or other fluids and stay in shaded areas as far as possible.
The young and the elderly are most vulnerable to heat waves and they should take extra care. After every meal, have one glass of water and try to replace other drinks such as coffee and tea with it. Drink a glass of water immediately after waking up as your body would have been without it for several hours (depending on how much you sleep!). If your workplace is very hot, take regular water breaks. In the end, the thumb rule to prevent a heat stroke is: "Drink early, Drink Often!"
Can you tell me how a sunscreen works?
A sunscreen works on a combination of organic and inorganic materials. While the inorganic ingredients (such as zinc oxide or titanium oxide) reflect Ultra-Violet (UV) radiation, organic elements (such as oxybenzone) absorb the radiation and let it out as heat. UV radiation can be broken into radiations of three different wavelengths: UV-A, UV-B and UV-C. Sunscreens usually protect us from UV-B rays which are responsible for sunburns. While buying a suncreen, you should look at the Sun Protection Factor (SPF). It is used to measure how effectively the suncreen blocks the UV-B radiation. The higher the SPF, better the protection.
What is animal testing and why are certain people opposed to the concept?
Animal testing involves use of animals by various bodies such as universities, government agencies, pharmaceutical companies, etc. for different types of experiments.
Scientists study an animal's response to a certain stimulus and the results are used to improve one's knowledge and develop better products for humans.
Animal testing has proved to be useful in developing vaccines against polio, measles, rabies, etc. Development of antibiotics, HIV drugs, and cancer treatments also employ animal testing. Usually, the animals are euthanised after the experiment. Some of these animals are caught by people who supply them to different institutions where they are "purpose" bred.
However, there are people who see this practice as inhuman and nothing short of murder and have spoken against it. They feel that animals have as much right to live as humans. Others question the very purpose of animal testing since animals react in different ways than humans do.