latest science news Archives - Champak Magazine

Make A Sundial

A sundial is a device that tells time using the position of the Sun, or more precisely using its hour angle, or sometimes its altitude.

Things you need:

• Mount Board • A Sweet Box Protractor Ruler Glue Box Cutter Sketch Pen White Paper

_______________

Telling Time

A sundial is a time keeping device that measures time using the position of the sun. The earliest sundials were used by ancient Egyptians around 3500 B.C.

___________________________________________________________

Do:

Wrap your box with white paper. Draw a base line at the bottom.

___________________________________________________________

Mark out points 15° apart using a protractor, starting from the base line.

___________________________________________________________

Draw lines from the center through these points. The sundial’s face is now ready.

___________________________________________________________

To make the gnomon cut the shapes as shown from mount board.

___________________________________________________________

Fold the strips in an ‘L’ shape and paste them on either side of the triangular piece.

___________________________________________________________

Paste the gnomon along the middle line of the sundial and label as shown on the next page.

___________________________________________________________

Think about:

Water clocks

Since sundials can’t be used indoors or after sunset, the Greeks, Romans and Egyptians used a water clock or a clepsydra (klep-sid-ra). These devices would measure time with the help of a stream of water flowing from a container. The water would fill another container with markings which would tell what time it was. With time, water clocks became more complicated and hourly intervals would also be marked by chiming bells, moving figurines etc.

___________________________________________________________

Find Out:

Jantar Mantar

The world’s largest sundial is at the Jantar Mantar in Jaipur and is called the Samrat Yantra. It was built by Sawai Jai Singh between 1727 and 1734. The Samrat Yantra stands 27 meters tall and is accurate up to two minutes of the actual time.

___________________________________________________________

See:

How to use the sundial

You can adjust a sundial with a magnetic compass or a watch. For it to work properly it needs to face north. This is because the sun moves from east to west. If our sundial faced east or west, the shadow of the gnomon (the time-telling edge) would fall under it. By aligning the sundial on the north-south axis with a compass, we can get the longest shadows. Once placed a sundial must not be moved. The sundial can also be calibrated with a watch by simply placing the sundial in such a way that the time according to your watch is the same as what the sundial reads. For example, if the time according to your watch is 1:00 p.m., adjust the sundial in such a way that the gnomon’s shadow touches the 1 p.m. line.

Since sundials tell the local time according to the sun, it may be off from the current time.

DISAPPEARING COLOURS

_________________________________

1. Use the lid to trace a circle on the white paper and cardboard. Cut both of them.

_________________________________

2. Using a pencil and scale, divide the circular sheet of paper into 6 equal parts as shown, and colour each in a different colour: purple, blue, green, yellow, orange and red.

_________________________________

3. Glue the paper to the cardboard.

_________________________________

4. Make a small hole in the centre of the disc and poke a skewer through it. Hold the skewer and spin the colour disc.

_________________________________

See

As you spin the disc fast, you will see that the different colours start to merge and appear as one colour (white).

_________________________________

Think about

Why do the different colours combine and appear white?

First, the colours combine and appear as one because of the way our eyes read moving images. When the disc spins, our eyes cannot register the colours separately, and hence perceive them as one. Second, the colours combine and appear white because of the composition of white light. All types of light travel in waves of different frequencies. Our eyes can only see lights that travel within a specific range of frequency called the visible spectrum. This spectrum consists of lights of different colours: red, orange, yellow, green, blue, indigo, and violet. When these colours are combined or travel together, they fuse into one to form white light. So, when the disc spins, the colours combine and appear white.

Let’s Find Out

How are rainbows formed?

The (white) light that we receive from the sun is composed of several colours. When a beam of sunlight passes through rain drops (which is why we see rainbows mostly during the monsoon), at a certain angle on its way down, it splits into the different colours it is composed of, thus forming the rainbow.

Photo credit: Pixabay.com

Deep sea creature

Every birthday, we grow a year older. Our body also ages with time. This is true of most living beings, except a type of jellyfish that has the ability to reverse its life cycle!

Turritopsis dohrnii, a species of jellyfish lives in the Mediterranean Sea and in the waters around Japan. This small bell shaped jellyfish grows up to 4.5 mm in diameter as well as in height—that is about the size of a fire ant.

Generally, a jellyfish starts life as a polyp—a cucumber-shaped organism that attacks itself to the ocean floor or a coral reef. Depending on the species, a polyp takes between a week and a month to grow into an adult.

When an adult Turritopsis dohrnii is injured, it goes to the bottom of the ocean floor and transforms back into a polyp—its infant state. It does so by first retracting its tentacles and then gradually shrinking its body. Once it reaches its polyp state, it starts to grow back into an adult jellyfish. This makes the jellyfish immortal. It has the ability to do this over and over again, until it is either eaten by a predator or dies of some disease.

Turritopsis dohrnii has inspired scientists to use this process of “rebirth” to try and renew damaged or dead human tissues of a dysfunctional organ and restore it to its normal state.

MAKE A PARACHUTE

Stuff

Plastic cover/ bag
String
Scissors
Scotch tape
Your favourite action figure (should not be too big) or a small stone

1. Using a large circular lid or any circular object, trace a circle on the plastic cover and cut it out.

___________________________________________

2. Mark eight points along the edge of the circle as shown. The points should be equally spaced.

___________________________________________

3. Take eight strings of equal length (each about 50 cms long). Stick one end of each string to the markings on the circle.

___________________________________________

4. Tie all the loose ends of the strings into a knot and attach it to your action figure or stone using tape.

___________________________________________

See

When you drop the action figure or stone from a height, it lands gently on the ground as the parachute opens up and slows down the fall.

___________________________________________

Think about

How does the parachute slow the fall?

An object falls because the force of gravity pulls it down towards the ground. When the parachute attached to the object opens up, its surface area increases. Thus, it traps a large amount of air under it, which offers resistance to the falling object. Now, there are two forces that are acting on the object: gravity and air resistance it is similar to someone trying to you push you back when you are trying to move forward). The air resistance caused by the air trapped under the parachute is greater than the gravity acting on the object, and hence the fall is slowed down.

Let’s Find Out

What are the uses of a parachute?

A parachute is used to slow down the jump of people or fall of things from heights, ensuring they can land safely: soldiers use parachutes to land safely after jumping off planes; fighter jets use parachutes to slow themselves down after they land on aircraft carriers; packets of food and medicines are tied to parachutes and dropped from planes into areas affected by natural disasters.

How To Make An Easy RotoCopter

SLIPPERY CARDBOARD

Stuff

A coffee mug
A small piece of cardboard
A rubber ball

1. Place the coffee mug on the table and cover it with the piece of cardboard and place the ball on it.

__________________________________________

2. Slowly pull the sheet and observe what happens.

__________________________________________

3. Now, again put the sheet back in place with the ball on it.

__________________________________________

4. This time flick the sheet with your index finger very quickly. Observe what happens.

__________________________________________

See

When you slowly pull the sheet, the ball doesn’t fall off. When you flick the sheet with your finger, the sheet flies off but the ball doesn’t. It falls into the coffee mug.

__________________________________________

Think about

Why does the ball fall into the glass when you flick the sheet off the glass?

Newton’s First Law of Motion states that a body at rest stays at rest and a body in motion stays in motion unless acted upon by an outside force. When you are in a moving car you are going at the same speed as the car. When brakes are applied, the brakes stop the car but not you. You move forward till your seat belt stops you. Here, when the paper sheet is slowly moved, the ball moves along with it because of friction between ball and sheet. Friction is the force between one surface and another. The friction between the ball and sheet causes the ball to move along with the sheet. When the sheet is flicked away quickly with your index finger, the ball does not move along with the sheet as the speed of the applied force is more than the friction between ball and sheet. The force of gravity on the ball makes it fall into the glass.

Math in Nature

Mathematics is everywhere around the world. We observe it rarely and enjoy nature instead of understanding the mathematical concept behind it. Below are some examples which exhibit Math in Nature beautifully.

______

The Italian mathematician Leonardo Pisano Bigollo, born in Pisa was also known as Fibonacci. French historian Guillaume Libri gave the name Fibonacci to Leonardo. Leonardo introduced a unique sequence of numbers that was then named the Fibonacci series or sequence after him. Fibonacci introduced to the world a sequence of numbers, that start with zero and one, and the next number in the series is obtained by the addition of the first two numbers. Zero and one when added gave one. 1 added to 1 gave 2, the fourth number in the series, and then 2 added to 1 gave 3, then 3 added to 2 gave 5 and simply put, adding the last two numbers gave the next one till infinity. So, the series would be 0,1,1,2,3,5,8,13,21,34 and so on. When these numbers are represented in a diagram form, it is called The Golden Ratio.

The Fibonacci sequence became famous because patterns were found in nature that followed this sequence.

Fibonacci Series and the Nautilus Shell

In a particular kind of seashell called the Nautilus shell the size of the spirals in the shell, when measured in proportion to the previous one, follow the Fibonacci sequence. A Greek mathematician, Phidias, developed the golden ratio diagram that illustrates the Fibonacci sequence. When this is superimposed on the shell, we can see the spiral in the shell, grows from smallest at the centre to be bigger as it gets towards the shell’s opening.

The spirals of the shell follow the Fibonacci sequence.

Latin word Nautilus means sailor. It is a marine mollusk (a shellfish) that is found only in the Indo-Pacific waters. They “live among the deep slopes of the coral reefs. The shell structure of the Nautilus has been unchanged more or less, for millions of years. Belonging to the cephalopod family (symmetrical and soft-bodied sea creatures), the shape of the chambers in the shell matches the Fibonacci sequence.

______________________________________________

Trees

Fibonacci sequence is found in the way trees grow. Unlike a mess of tangled branches, we see a pattern in the way the number of new branches that sprout from the previous branch. In the diagram, if we consider the trunk as one, then we can see how two branches form, then three, followed by five branches and so on. The number of branches keeps on increasing as long as the tree continues to grow.

______________________________________________

Hurricanes

Hurricanes also display the Fibonacci sequence in their formation. When we superimpose the golden ratio diagram over a satellite image of a hurricane, the way the hurricane spirals out again matches the number ratio of the Fibonacci sequence. In this case, a lot of factors make it look like that, the way the wind blows, air temperature, air pressure and so on. It’s just another manner in which mathematics expresses itself in nature.

______________________________________________

Roses

Fibonacci sequence is also seen in the way the rose petals are delicately wrapped around each other from the time it’s a rosebud till the time the rose is fully in bloom. No one really knows why this pattern is followed, but it just does. There is order even in chaos.

MAKE A RICE MAGNET

Things required:

A balloon

A woollen sweater

Puffed rice

________________________________________

Do:

1. Spread the puffed rice flakes on a table.

__________________________________________

2. Blow up a balloon and tie it.

__________________________________________

3. Rub the balloon vigorously against a woollen sweater.

__________________________________________

4. Bring the balloon near the puffed rice flakes.

__________________________________________

See:

The puffed rice flakes get attracted to the balloon and stick to it.

__________________________________________

Think about

Why do the rice flakes stick to the balloon?

All matter is made up of atoms. Inside an atom are protons, electrons and neutrons. The protons are positively charged particles, the electrons are negatively charged, and the neutrons are neutral, with no charge. In nature, opposite charges attract. Like charges repel. Static electricity is the result of an imbalance between positive and negative charges in an object. When the balloon is rubbed on a woollen sweater, electrons from the sweater get transferred to the balloon which then gets a negative charge due to excess electrons. When the balloon touches the puffed rice flakes, they get stuck to it because the rice particles are positively charged.

Winter Animals Winter Sleep

Trees shed their leaves. People wear jumpers and parkas and at home turn the heater on. But what about the animals? How can they survive low temperatures, long chilly nights and the lack of food?

Animals have developed few strategies to get through winter. They migrate to warmer places, they adapt to the season or they fall asleep and remain inactive until external conditions suit them better. This long, very deep sleep over winter time is called hibernation.

The coolest winter hibernators on Earth are:

Alpine Marmots

(Marmota marmota) are quite sleepy animals. Found in the mountain areas of central and south Europe, they hibernate for up to 8 months.

___________________________________________

Bats

They might be the sleepiest animal on Earth. In captivity scientists have recorded a big brown bat that spent 344 days sleeping away!

___________________________________________

Common Poorwill (Phalaenoptilus nuttallii)

It is the only known bird species to hibernate. This bird sleeps for up to 5 months.

___________________________________________

Bears

They are not always found in hibernation, except for 4 species: American Black Bear, Asiatic Black bear, Brown bear and Polar bear. Then their sleep is not a real deep one. They can wake up at any moment. So beware!

___________________________________________

Bumblebees

They die at low temperatures but the queen bumblebee hibernates in a hole in the ground for 6 to 8 months. As soon as weather conditions warm up the queen wakes up and works to create a brand new swarm.

___________________________________________

Common Box Turtle (Terrapene carolina)

They can hibernate from 80 to 160 days. This length varies according to location and turtle subspecies. These turtles are very delicate. If they get up too early, they may not survive to winter.

___________________________________________

Snails

They can hibernate for years. They just need to lock them inside their shell and wait for the right time to get up and go out.

___________________________________________

Garter snakes are social. They hibernate in groups for warmth and as soon spring arrives and temperature goes up, they, in group, go out of their winter homes. People who see them say it’s quite amazing.

___________________________________________

Hedgehogs can sleep through the whole winter in their in their burrows.

Albert Camus (1913 – 1960) French Nobel Prize winning author, journalist, and philosopher told us why: “In the depth of winter, I finally learned that there was in me an invincible summer.”

SEO Keywords: latest science news

Make A Sundial

DISAPPEARING COLOURS

Deep sea creature

MAKE A PARACHUTE

How To Make An Easy RotoCopter

SLIPPERY CARDBOARD

Math in Nature

MAKE A RICE MAGNET

Winter Animals Winter Sleep

Stories | Puzzles | Knowledge | Comics | Craft | Parenting | Careers | About Us | Contact Us | Terms & Conditions

Copyright © 2023 - champak - All Rights Reserved