Category Everyday Science

What are the different stages of vaccine development?

Nine months into the COVID-19 pandemic, scientists and pharmaceutial companies around the world are racing to develop an effective vaccine against SARS-CoV-2, the coronavirus that causes COVID-19. According to the latest list of the World Health Organization (WHO), at least 200 vaccines are at various stages of development.

According to Russian State media, the first batch of Russia’s vaccine, Sputnik V, entered “civil circulation” on September 24 in capital Moscow. However, its safety and effectiveness is being looked at sceptically because the results of only the phases 1 and 2 of the trials have been published. Earlier, reports emerged that the third stage trials were ongoing in Russia and a few other countries. Phase 3 of clinical trials of the Sputnik V vaccine will begin in India in the coming weeks.

China has about 11 vaccine candidates in various stages of human testing. China has been administering experimental coronavirus vaccines to large numbers of workers deemed to be at high risk of exposure to the virus. They include frontline health workers, public service workers and border officials. A vaccine developed by CanSino Biologists and named Ad5-nCoV was approved for use within the Chinese military as early as June 2020. Four other vaccines are in the final stages of clinical trials. Chinese officials say that the country will be able to roll out a vaccine for public use by November or December. China has promised to provide doses to at least 62 countries.

Among other vaccine contenders that have drawn global attention is the one being developed by the Oxford University in partnership with phaemaceutical company AstraZeneca. Hopes were high when it successfully carried out phases 1 and 2 of the trials. But the final clinical trials had to be briefly put on hold in September after a study participant developed a suspected serious adverse reaction.

COVID-19 vaccines are also being developed by Pfizer and BioNTech in the U.S. and Germany; Johnson and Johnson in the U.S.; Sanofi along with GlaxoSmithKline in the U.K. and Franc; and Novavax in the U.S. Some of these companies have signed deals with multiple countries for trials.

Back home, in India, there are at least eight vaccine candidates under development. The phase 3 clinical trial of ‘Covishield’, being developed by Oxford University and the Serum Institute of India, is underway. Indian candidates, Covaxin, by Bharat Biotech, and ZyCoV-D, by Zydus Cadila, are currently in phase 2 trials.

Experts maintain that even at this speed a vaccine will not be ready before mid-2021.


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What happens when you put water on a candle?

Warm the base of a candle and stick it to the bottom of a small bowl. Pour water into the bowl till the water reaches the rim of the candle. Light the candle. It will burn and the flame will form a crater in the candle.

The base of the flame will sink below the surface level of the water, but the water will be prevented from extinguishing the flame by the thin wall of wax that is left standing all around it.

How does the wall form?

The water takes up so much heat that the outer layer of the candle does not reach melting point. As a result, the wax there cannot evaporate and burn. It remains like a wall around the flame.


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Before cooking an egg, how do you find out if it is fresh or stale?

Immerse the egg in a bowl of water. If the egg lies horizontally on the bottom of the vessel containing the water the egg is probably fresh; if the egg stands on its pointed end, the egg may be several days old.

What is the basis for testing of freshness of eggs in this way?

Eggs contain tiny pores invisible to the naked eye, through which air can enter or leave the egg. The air in the egg is contained in the air cell situated at the broader end of the egg.

Due to the gradual evaporation of water from the egg after it has been laid, the air cell becomes larger as the days pass. This makes the broader end lighter than the rest of the egg, so if an egg that is several days old is placed in water, the broader side will float upward causing the egg to stand on its pointed end.


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What are the great scientific discoveries?

Life is full of problems, and scientists are always trying to find new ways to solve them. There are hundreds of great scientists who have changed our lives for the better,through their discoveries and their inventions. Here are seven of them.


Charles Darwin worked out how animals, such as moths and beetles, can change over many generations to become new species. This process is called evolution.


Ada Lovelace wrote the first published computer program. She also predicted that a computer would be able to make music and images, not just do sums.

Light bulb

Thomas Edison is best known for inventing the first light bulb that could be made in large numbers. He also invented a sound-recorder and a moving-image projector, which helped to start the age of movies.


Issac Newton is said to have discvered how gravity works when he saw an apple fall from a tree. He realized that there must be a similar force that keeps the Earth moving around the Sun.


Marie Curie discovered two substances, called radium and polonium, which give off invisible rays that can pass through materials. She called these rays radioactivity.


Albert Einstein’s theories of relativity, along with his ground-breaking E = mc^2 equation, helped scientists to understand the Universe, and how energy, mass, space, and time are all related.


Alexander Fleming discovered penicillin, which led to the creation of a group of medicines called antibiotics. They kill the bacteria that cause many infections in humans and other animal, and so have saved millions of lives.


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What is the human skeleton made of?

Like all vertebrates, humans have a bony skeleton underneath their skin and muscles. It is a framework to hold up the body, help it move, and protect what is inside. The amazing brain makes humans the cleverest of all the animals. That includes you!


The brain controls the body, sorting out information from the world around you and sending out instructions. It also stores memories.


With each beat, the heart pumps blood around the body, delivering nutrients and oxygen to every part.


Lungs bring air into the body through breathing. This air contains oxygen, which is needed to keep the body alive.


The body needs food to survive. The digestive system breaks food down, keeping the nutrients and getting rid of the waste.

Strong muscles

Muscles are like elastic straps that can stretch or squeeze. Many muscles move the body by pulling on the bones.

Standing tall

Unlike most animals, humans walk upright on two legs. This allows the arms to be used for other activities such as making things.

Body facts

  • Human skeletons contain more than 200 bones. The smallest bone is inside the ear and in only 3 mm (3/25 in) long.
  • The thigh bone is the strongest bone in the body. It is about four times stronger than concrete.
  • A human heart beats more than 100,000 times in a day. That is over 35 million times in a year.
  • In one day, blood travels about 19,000 km (12,000 miles) around the body.


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What are Animals?

There are millions of different types of animal on Earth, so scientists have divided them into groups, based on features that they share. For example, is their body covered in fur, feathers, or scales? The amazing imaginary animal shown here combines key parts of animals from six well-known groups.


All insects have six legs and a pair of feelers on their heads, like this moth. Most of them have wings and can fly.


Reptiles are covered in hard, dry scales, or a shell, like this tortoise. They have either four legs or no legs at all.


Mammals have fur or hair on their bodies, and feed their babies milk. Humans are a type of mammal.


Birds have wings, and they are the only animals that have feathers, which keep them warm and help them to fly.


All fish live in water and use their tails to help them swim. Their bodies are covered in scales, and they have gills for breathing underwater.


Amphibians live both on land and in water. Most of them have four legs, which they use for walking and swimming.


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How is science involved in everyday life?

Science is all around us. From the moment we wake up to the moment we go to bed, almost everything that we do or that happens to us can be explained by science. Here are a few examples of the ways that science helps us to understand what goes on in our daily lives.

Wakey wakey!

Science explains how a cockerel could wake us up in the morning. Sound waves travel through the air from the cockerel’s mouth to our ears.

Light the way

Science explains how flicking a switch turns on our lights, by allowing electricity to flow around an electrical circuit.

Keeping warm

Science explains how our clothes keep us warm. Wool and cotton are poor conductors of heat energy, so they stop our body heat from escaping.

Eat up!

Science explains why we need to eat food every day. Food contains stored energy that we need in order to move, grow, and keep warm.

On the move

Science explains how wecan use a bicycle to travel quickly. The grip of the tyres produces friction between the wheel and the road, which helps to push the bike along.

Sun power

Science explains why a plant grows when we put it on a windowsill. Plants use energy from sunlight to produce food, which gives the plant energy to grow.

Ball games

Science explains why a ball moves when we kick, throw, or hit it. Our arms and legs produce a force that propels the ball forwards.

Time for bed

Science explains why the Moon stays in the sky. The force of gravity from the Earth pulls on the Moon, keeping it in orbit around our planet.


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How plants spread their seeds?

Seeds contain everything needed to form a new plant. To do that, they need to be scattered away from the parent plant to a new place on the soil where they can grow. Different types of plant have different ways of spreading their seeds. Some need animals to move them, while others use wind or even fire to scatter them.

Blow in the wind

Some plants have very light seeds and so can use the wind to spread them. This dandelion has seeds with tiny parachutes that allow them to be carried away when the wind blows.

Tasty treats

Many plants have seeds that are hidden inside tasty fruits, such as berries. When an animal eats the fruit, the seeds pass through its body unharmed and are released in its droppings.

Sticky seeds

Animals can carry seeds away from plants without even realizing it. Sticky seeds will fix on different parts of their body, while some seeds, called burs, have little hooks that attach to the animal’s fur.

Exploding pods

The Himalayan balsam plant keeps its seeds in pods. These pods explode when they are ripe, shooting the seeds out of them. The explosion can scatter the seeds up to 7 m (22 ft) away, often startling unsuspecting passers-by.

Earth, wind, and fire

Some plants have more dramatic or unusual ways of spreading their seeds. Fire may kill the parent plants, but it leaves behind fertile ash for their seeds to grow in.

Heat treatment

Jack pine cones are glued shut with resin. When a fire sweeps through the trees, the resin melts and the seeds are released.

Desert rover

Tumbleweed is the dried-up top part of some plants. It rolls around the desert whenever the wind blows, scattering its seed as it goes.


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What are Plants?

Plants make their own food using sunlight. Most plants are held in the ground by their roots, and have green leaves. There are thousands of types of plants, ranging from huge oak trees to small ones like this fuchsia.


Plants usually grow in the earth or soil. The roots dig deep into the ground, keeping the plant in place. They also soak up mineral salts and water from the soil.


The stem supports the leaves and flowers holding them up towards the light. The stem also carries water and nutrients in the form of mineral salts from the roots to the rest of the plant.


Plants use their green leaves to capture energy from the Sun’s rays. The leaves use this energy, together with carbon dioxide from the air, and water, to make food for the whole plant.


Most plants have flowers for reproduction. They have male pollen and female eggs, which join together to make seeds.


Fruits, such as berries, are the parts of flowering plant that contain seeds. Once in the ground, the seeds will grow into new plants.

Why we need plants?

Nearly every animal relies on plants in some way or other. Some animals, called herbivores, eat only plants. Human grow lots of types of plants just for their flowers. Some types of tree are grown for their wood.


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What are Living things?

All living things have certain characteristics in common. To count as being alive, a living thing has to be able to carry out seven different processes, which are listed below.


All living things can move on their own. Even plants have leaves that turn to face the Sun.


Living things can produce new versions of themselves.


Living things can detect and respond to changes in the world around them. For example, the ability to react to changes in light, or to hear sounds.


Living things get bigger as they get older until they reach their full size.


All living things turn food into energy, using oxygen from the air.


All living things must get rid of any waste that they produce.


All living things need food. Unlike animals, plants make their own food.


Animals can move from place to place. They cannot make their own food, so they rely on eating other living things to survive.


Plants are fixed in the ground, but their roots, leaves, and flowers can move. They make their own food by using the Sun’s rays.


Funguses may not look alive, but they are. Most funguses feed on the remains of dead plants or animals. Mushrooms, toadstools, and moulds are all funguses.

Tree trunk

When a tree dies it usually falls to the ground. Funguses can grow on the dead tree trunk and soak up its nutrients.


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