7.35 to 7.45

By Jora Singh Nahal
Elementary Category (Grades 4-6)
Experiment | Biology, Chemistry

My project is about pH. pH stands for ‘potential of Hydrogen’ which measures the acidity or alkalinity of any water-based solution on the pH meter ranging from 0 to 14, where 0 being the most acidic and 14 the most alkaline /basic, and 7 being the neutral pH (as shown in Figure #1 in ‘Background Research’).

The pH of our blood is extremely important for our health. The normal healthy blood pH has a very narrow range from 7.35 to 7.45 and a slight change in it, if left untreated, can be dangerous or even fatal. If the blood pH falls to 6.9, the person goes into ‘coma’, and if it falls below 6.8 or rises above 7.8, the person dies. So, our blood pH level is extremely important! A change in the blood pH balance can lead to medical conditions called ‘acidosis’ (when blood pH falls below 7.35 and become too acidic), and ‘alkalosis’ (when blood pH rises above 7.45 and become too alkaline). Any changes in the normal blood pH might be a sign of certain medical emergencies, such as, asthma, diabetes, heart disease, kidney disease, lung disease, gout, infection, hemorrhage (bleeding), drug overdose, and poisoning etc.

But, our body has a very amazing self pH balancing mechanism, and the two important organs that play a key role in this are the lungs and kidneys. Lungs remove excess acid from our body through respiration- it removes carbon dioxide (which is slightly acidic) during exhaling. And kidneys remove excess acid from our body through urine (excretion). Moreover, to balance the excess acid in our body, our body uses calcium (which is basic/ alkaline) from our bones and teeth, and use it as a buffer to balance pH, and that’s why according to many experts, acidic foods badly affects our bone health (leads to osteoporosis). So, we should limit acidic foods such as meat, dairy, sweets, & processed foods, and eat healthy alkaline foods, such as lots of fruits and vegetables (Figure #2 in ‘Background Research’).

Not only the pH of our body is extremely important for good health, but also the pH of drinking water, soil, rain water, different water bodies, food, etc are also very important for our health, and for the health of fish, other aquatic life, plants, and our ecosystem because if it goes beyond the normal range then plants, fish and other aquatic life die (shown in the table in ‘Background Research’).

That’s why for my project, I tested the pH of around 70 samples, and I used all the 3 different methods to measure pH: pH test strips, pH liquid indicator, and a pH meter. For Experiment #1, I tested the pH of around 50 samples of our urine and saliva to analyse if it’s the same or different, to analyze if our urine pH depends on our age, gender, health conditions, and sample timing, and also to analyze the effect of eating alkaline foods on our urine pH. For Experiment #2, I tested the pH of around 20 different samples, such as, the rain water, drinking water (tap or bottled), different water bodies (river, lakes, ocean, and wetland), and swimming-pool, to analyze if its pH is in the normal range or not.

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