SHIP IS LIGHTER THAN WATER!

Why the city like ship floats on the water? For the simple question, the simple answer is ship is less denser than water. Yes, really. The ship is designed and shaped so that it average density (mass/unit volume) is less than that of water. That is why the ship can only have ship-shape. But the usual explanation is based on Archimedes principle.

In this article, we are going to speak about density, even though it appears to be elementary concept, it has deeper meanings.

Density indicates how much matter is really packed in the unit volume. Common sense says, cotton package is lighter than a bar of iron. Physics says, mercury is 13.6 times heavier than water. That is, 1 cc of water weighs 1 gm. But 1 cc of mercury weighs 13.6 gm. Hence mercury is used in pressure-meters, thermometers etc,.

Osnium is the heaviest metal available in nature(density 22.6). Platinum, iridium, gold, silver are also heavy. Osmium and platinum are used in pacemakers and in artificial heart-valves.

The known lightest material is Aerogel. It is the gel like substance in which liquid is dried up and replaced by air. It is also called 'solid air', 'solid smoke' etc,.
Aerogel made up of graphene (carbon) is known as aerographen. It is very light. It's density is 0.16 milligram/cc and 7.5 times less dense than air. It can absorb up to 900 times its own weight in oil and water, making oil spill clean ups a potential application.

An atom has lot of empty space in which the electrons whirls around. All the heavy matters proton and neutrons are packed in the tiny nucleus at the center due to strong nuclear attractive force. Hence the nuclear density is highest and it is 2.3*10^17 kg/m^3.

When some stars run out of life, they collapse into a body of nuclei called neutron star. They are very dense and heavy and hence they have enormous gravity. Even the light that falls on it cannot escape, so they are also named black hole.

Astrophysicists say: Once the entire universe was contained in a tiny point that is like a dot at the end of this sentence. The point had infinite density. It is then exploded as the 'big bang' and the universe was born.

Some times we want to hear light music and read light stories. Sometimes we have to go for denser materials.

Comments

THE EARTH, A SUPER ORGANISM

JOIN MY COURSE: "Become a programmer in a day with python" A man called 'love lock' (what a name) proposed a theory called Gaia theory, named after Greek Goddess. It says, "Earth is a self-regulating organism like a human being. The organic life in it interacts with in-organic matter and maintains atmosphere, temperature and environment". Hence the earth is still suitable for the life to thrive. Imagine, in a particular place, there are lot of flowers. Some flowers are white and some are darkly coloured. We know, white reflects light and heat while dark absorbs the same. White flowers can thrive in hot climate. But dark flowers requires cold climate. The absorption and reflection balances and the environment reaches average, warm temperature at which both the flowers can co-exist. This is the essence of "Gaia" theory. On our earth, ...

DISORDER IS THE "ORDER OF THE DAY"

Imagine a balloon full of air. The air molecules are moving randomly inside the balloon. Let us pierce the balloon with a pin. The air rushes out. Why should not the air molecules stay inside the balloon safely and ignore the little hole? That is not the way the world works. The molecules always "want to occupy as many states as possible". Hence the air goes out in the open to occupy more volume. The things always goes into disorder (entropy) and the disorder increases with time. The above statement is what we call "second law of thermodynamics". Consider a cup of coffee on the table. Suppose the heat from entire room flows to your cup of coffee, the coffee will boil and the rest of the room will freeze. Freezing means bringing things to order and arrangement. It violates the second law. Hence it will never happen. Hence heat must flow from high ...

CASINO'S GAME

Let us find out how the casino survives with mathematics. Say, your friend invite you for a game of dice. You must bet (wager) 2 dollars. If you roll 'six' you will get back 8 dollars. The game will go on for 30 rounds. All sounds good. The probability of rolling 'six' is 1/6. Since the game will be played for 30 times, the 'expected win' is 30*1/6 = 5. That is, you are expected to win 5 rounds out of 30. Hence your gain will be 5 * 8 =40 dollars. ok. This also implies that you will loose 25 rounds. Hence your loss will be 25*2 =50 dollars. Your net gain will be gain-less = 40-50 = -10 dollars. For 30 rounds, the loss is -10 dollars, Hence, for one round =-10/30 = -1/3 dollars. There will be a loss of -1/3 or 0.33 dollars per round. It is not a fair game. Let us make a simple formula to calculate 'Pa...

sciencecapsules

Search This Blog