Category Chemistry

What makes it snow?

Take a close look at some snowflakes. You can see that they aren’t drops, like rain; or lumps, like hail; or tiny beads, like sleet. They look more like little feathers.

Snow forms when water vapour in clouds freezes. It forms at the top of storm clouds where the air is colder. The frozen water drops grow as more water vapour freezes onto them. They turn into tiny, clear pieces of ice called snow crystals. A snowflake is actually a bunch of snow crystals.

When you look at a snowflake through a magnifying glass, you see a beautiful, lacy shape. Even when they may seem the same, no two snow crystals are exactly alike. Some are flat. Others are shaped like long needles. Most look like pieces of lace. Yet, in one way they are almost all the same. Almost all snow crystals have six sides.

Snow can form high in the sky even in summer. But when snow falls in summer, it melts and becomes rain as soon as it reaches warm air lower down.

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What is air made of?

Air doesn’t seem to be made of anything. It has no colour, taste, or smell, and you can see right through it. But air is made up of things. It is made of many kinds of gases. And these gases are made up of tiny bits called molecules.

Actually, everything on the earth is made up of molecules. Solid things, such as plants, animals, and rocks, are made of molecules. So are liquids, such as water, and gases, such as the ones in air.

In solids, the molecules are packed close together and hardly move. In liquids, the molecules are further apart and move faster. In gases, the molecules are very far apart and zip about rapidly. That’s why gases are so light that you can’t see them.

For us, the most important gas in the air is oxygen. We breathe to get oxygen into our bodies. Almost every kind of animal and plant in the world must have oxygen, or it will die.

Only about one-fifth of the air is made up of oxygen. Most of the air – nearly four-fifths – is nitrogen. The rest of the air is made up of many different gases. Water vapour and dust float in the air, but they are not part of the air.

If air is just floating gases, why doesn’t it float away into space? Because the earth’s gravity pulls at the air just as it pulls at you. The air can no more float off into space than you can!

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What is net-zero emission?

The U.S. president-elect Joe Biden has declared that the U.S. will return to the Paris Agreement and vowed to reach net-zero emission by 2050. China has committed to achieving net-zero carbon emissions by 2060. South Korea, New Zealand, Australia, Brazil, Iceland and scores of other countries and corporates such as Pepsico have all set net-zero goals. A new study shows that climate disaster could be curtailed within a couple of decades if net-zero emissions are reached.

So, what does net-zero mean?

Do not be confused with the word ‘zero’. Net-zero emission does not necessarily mean reaching zero emission. Under a net-zero scenario, emissions will still be generated, but this emission must be removed from the atmosphere through measures such as reforestation and artificial carbon sequestering. In other words, net-zero means achieving a balance between the greenhouse gases put out into the atmosphere and those removed. The term “carbon-neutral” is sometimes used instead of net-zero, and they broadly mean the same thing. It’s not just countries that can achieve net-zero emissions, even a state, city, company or a single building can also strive to achieve net-zero emissions.

However, climate activists such as Greta Thunberg are demanding for zero emissions, meaning no emissions are produced in the first place.

How can net-zero be achieved?

  • By reducing the use of fossil fuels and by adopting renewable energy sources.
  • By developing energy-efficient technologies. 
  • By adopting massive reforestation or tree-planting measures.
  • By investing in technologies such as carbon sequestration that can remove carbon from the atmosphere. Carbon sequestration is the process of capturing and storing atmospheric carbon dioxide underground permanently and safely.

However, no technology or quantity of trees planted could offset the emissions currently generated globally, unless every country and every household is part of this solution.

 

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What do chemists do?

Chemists. One of the physical sciences is chemistry. Chemists study chemicals and other materials to find out what they are made of. They also learn how these things change when they join with other substances. Chemists take molecules apart and put them together in new ways. They try to find out how chemicals can be used to make things people need, such as fuels, medicines, plastics, and thousands of other materials. Some chemists study how light, heat, and other forms of energy change chemical substances.

A chemist will often work as part of a larger research team in order to create much needed compounds for use in a wide variety of practical applications. A chemist also works to improve the quality of established chemical products and utilizes advanced computer programs to establish new technologies in the field.

Almost every industry benefits from the theories and chemical compounds brought about by research in the chemical sciences.

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What exactly is nuclear energy?

All things – even you – are made up of billions and billions of “bits” that are smaller than anything you can imagine. These “bits” are called atoms. Atoms are the tiniest parts that something can be broken into and still be the same stuff. For example, one atom of gold is the tiniest bit of gold possible.

Special machines can split certain kinds of atoms into even smaller parts. When atoms split, they give off energy. The part of the atom that splits is called the nucleus, so the energy is called nuclear energy.

The energy given off by atoms when they are split is in the form of heat. So a machine that splits atoms can be used the same way a fuel-burning engine is used. The machine makes heat. The heat can be used to run generators that make electricity and to run other machines, too.

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What is Chemical Energy?

You have seen candles burning. An orange flame dances around the wick, while the wax melts underneath and drips down. The candle gets shorter as the wax melts.

The candle wax has a kind of stored-up energy. It is a fuel. A fuel is something that is burned to make light, heat, or a push that makes things move. The coal, oil, and gas used to heat homes and other buildings and to cook food are fuels. The petrol in a car and the wood in a fireplace are fuels, too.

The same thing happens to every kind of fuel when it burns. When it starts burning, the heat makes it break down and change to other things, such as ashes. As the fuel breaks down, it gives off energy. Some of the energy is light, and some is heat.

When petrol is burned in a car engine, the heat energy makes the engine push. The push from the engine makes the car run.

The energy stored in a fuel is called chemical energy.

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