Send us your questions

Some of our visitors have sent emails with interesting questions, we decided to start having a space to answer them. In this space the blog "Restless Minds" will answer all questions you send us
Send us your question for the email: Restless Minds.

Science progress affects our daily life and "to know" means you are going to chose right, because it allows you to form your own opinion on scientific everyday issues. On the other hand, having an elegant and harmonious vision of the world where we live in leads to a feeling of intellectual satisfaction.
We believe this kind of scientific day to day knowledge should be encouraged from an early age, and that's why this project was born: science, culture, knowledge, crafts for your restless mind.

Tuesday, January 31, 2012

Instant facts- Just add water 37

The reflection is bouncing back of light waves when they hit an object with a very smooth and shiny surface, like a mirror.

Monday, January 30, 2012

DIY Refrigerator magnets

Use broken wood cloth pins to do some crafts with your young restless children.

Make sure you have several other small objects around, like cloth pin's or small beads.

We need:

  • wood cloth pins,
  • buttons, paper clips, beans, etc,
  • hot glue, works best,
  • small magnets,
  • thick cardboard,
  • craft knife.

How to:
  1. On the cardboard draw the outline you wish your magnet to have, we choose the letter M;
  2. Use the craft knife to cut the cardboard; this must have adult supervision, In the example the cardboard is too small, its better if the cardboard is at least the size of the pin;
  3. Use the small objects to decorate the magnet, attach them with hot glue, the white glue also works;
  4. Let it dry;
  5. Glue the cardboard to one of the pin's sides;
  6. Glue the magnet on the other side;
  7. Let it dry.
Et voilá!
Kitchen ART


Instant facts- Just add water 36

The Sun's mass is 2 x 1027 tonnes

Friday, January 27, 2012

DIY- Hovercraft with a CD

A hovercraft is a vehicle that glides over a smooth surface by hovering upon an air cushion.
Hovercraft was invented in 1953 by Sir Christopher Cockerell.

We need:

  • a CD, broken, of course,
  • glue, super-glue works best,
  • milk cap, we used a second cap with a secure valve, from a dishwasher bottle,
  • a nail;
  • a big balloon, bigger the balloon, bigger the hovercraft trip;
  • acrylic paint,
  • alcohol.
How to:
  1. Clean the CD with soap and alcohol;
  2. If you use the milk cap, the red cap in picture, punch it with the nail 3 times, if you are using the other one skip this step;
  3. Glue the cap to the CD hole, like the picture, the cap as a small contact surface and it must be fairly glued to the CD, this can be a hard task;
  4. Let it dry;
  5. Paint the CD if you wish;
  6. Let it dry again;
  7. Varnish it, and let it dry again;
  8. If you are using the milk cap:
    1.  Blow the balloon;
    2. Twist the tip of the balloon so the air can't escape;
    3. Carefully fit the balloon on the cap;
    4. Place it on the ground and let go;
  9. If you are using the cap with the spot system, like the white one in the picture:
    1. Attach the balloon to the cap;
    2. Open the valve; be careful you can detach it from CD;
    3. Blow the balloon using the bottom hole on CD;
    4. Close the valve;
    5. Place it on the ground and open the valve;
Using the cap with the valve is easier but will moves with both caps.

Air rushes out of the balloon through the hole to provide an air cushion below the CD. The air is escaping on all sides, and therefore this cushion supports the entire surface of the CD, just like a real hovercraft.

Et Voilá!
Fun fun fun!


Instant facts- Just add water 35

The prequel to The Lord of the Rings is now expected to cost $500 million (£315 million), it has been reported.
This would make it about $200 million (£125 million) more costly than the third part of the Pirates of the Caribbean franchise, thought to have been the most expensive film yet.

Thursday, January 26, 2012

Instant facts- Just add water 34

Women accounted for 6% of directors of the top 250 domestic grossing films released in 2007, a decline of 1% since 2006.

Wednesday, January 25, 2012

Instant facts- Just add water 33

Hermit crabs can live to 6 to 15 years.

Tuesday, January 24, 2012

Instant facts- Just add water 32

15% of people are left handed.

Monday, January 23, 2012

Grandfather Tang's Story

Ann Tompert (Crown Publishers, (New York, 1990)), published a book called Grandfather Tang's Story that uses Tangram 7 pieces as illustrations- you can learn more about Tangram here.
The idea can be very useful in a class room or even at home while playing with our restless.

The story goes like this:

Grandfather Tang

Tangram Grandfather Tang

and Little Soo

Tangram- Little Soo

were sitting under a peach tree in their backyard.

Tangram- Tree
They were amusing each other by making different shapes in their tangram puzzle.

"Let's do a story about the fox fairies, (Chou and Wu Ling)," said Little Soo. So Grandfather Tang arranged his seven tangram pieces into the shape of a fox.

Tangram- Fox
Then Grandfather Tang made another fox with Little Soo's seven tangram pieces. Little Soo clapped her hands as her grandfather began.

Although Chou and Wu Ling were best friends, they were always trying to outdo each other. One day this rivalry almost brought their friendship to a tragic end. They were sitting under their favorite willow tree beside a river talking about their magic powers.

"I can change myself into a rabbit as quick as wink," boasted Wu Ling. "I'll bet you can't do that."

"I can too," said Chou.

"Can not," said Wu Ling. "Anyway, actions speak louder than words." and he changed himself into a rabbit.

Tangram- Rabbit
"Not bad," said Chou, smoothing his whiskers. "But watch me do better than that."

And before Wu Ling could blink, Chou changed from a fox into a dog.

Tangram- Dog
Now, when Chou changed himself into a dog, he not only looked like a dog, but he felt like a dog and acted like a dog. He bared his teeth and lashed his tail. Wu Ling shivered and twitched his nose.

"I love rabbits," Chou growled," and I'm going to get you and gobble you up."

The dog edged closer and closer. Wu Ling's eyes grew bigger and bigger. He was too frightened to move at first. But then he thought, "I'll be safe if I can climb up the willow tree."

His little puff of a tail grew long and bushy and his tall ears shrunk as Wu Ling transformed himself into a squirrel.

Tangram- Squirrel
Wu Ling sprang into the willow tree and scrambled to the top.

"Chou will probably turn himself into a cat so he can climb up the tree after me," Wu Ling said to himself. "But he'll never catch me, I'll jump from tree to tree and he won't be able to follow me."

Of course, Chou thought about changing himself into a cat.

Tangram- Cat
"But that's just what Wu Ling expects me to do," he said to himself. "What can I do to surprise him?" He thought and thought. "I know. I'll swoop down upon him from above" And he turned himself into a hawk.

Tangram- Hawk
Chou circled round and round in the sky above the willow tree, searching for Wu Ling. Wu Ling peered through the leaves of the tree, looking for Chou on the ground. Round and round Chou circled the willow tree until he spied Wu Ling.

"Kek! Kek! Kek!" he shrieked as he zoomed down upon the squirrel.

Wu Ling trembled. Chou's beak looked sharp enough to pierce right through him.

"If only I lived in a shell house," he thought "Then Chou couldn't hurt me."

Chou stuck out his fierce claws to seize Wu Ling, but Wu Ling dove toward the river below the willow tree. And as he dove, he tucked in his head and tail and legs, turned green, and changed into a turtle.

Tangram- Turtle
Wu Ling climbed up on a mossy rock in the middle of the river. He thought he was safe because he looked as if he were a part of the rock. Chou circled round and round, searching and searching, until his sharp eyes spotted the turtle. Then he swooped down, down, down toward him.

But just as Chou reached him, Wu Ling plunged into the water. "Follow me and you'll drown, he cried.

"Don't worry," cried Chou, plunging right behind Wu Ling.

His body grew longer, covered with scales. He whipped the water with his long, wicked tail. And he snapped his spike-toothed jaws as he turned into a crocodile.

Tangram- Corcodile
Wu Ling circled round and round as he plunged down, down, down to the bottom of the river. Chou lashed his wicked tail as he plunged after Wu Ling. Just as they reached the bottom, Chou clamped Wu Ling in his spike-toothed mouth.

"Now, I've got you!" he bellowed through his clenched teeth.

"Oh, no, you haven't," cried Wu Ling, who grew smaller and smaller and changed himself from green to gold as he transformed himself into a goldfish.

Tangram- Goldfish
and he swam out of Chou's mouth between his spiked teeth.

Then he hid in a patch of cattails. Chou churned the water with his lashing tail as he charge into the patch after Wu Ling. With his head swinging back and forth and his eyes darting here and there, he searched for Wu Ling. Wu Ling knew that Chou would not give up until he found him.

"I must fly from here," he thought. And he started to honk as he transformed himself into a goose.

Tangram- Goose
"Honk! Honk! Honk!" called Wu Ling. And he took to the air.

A chorus of honks swelled the air as the flock of geese spread their wings to follow him. While Chou watched, the honking grew fainter, the flock grew smaller, and he felt his anger slowly drain away.

"Why, oh, why did we play that stupid game?" he moaned. "I'll never see Wu Ling again"

He closed his eyes and sank toward the river's bottom. Just as he touched it, however, he had an idea. And up he popped again, a goose himself.

Chou charged after him, but Wu Ling spread his wings and took to the air.

Chou watched him fly to a small island where a flock of geese were feeding. By now he was not only very angry, he was also very hungry. He decided that if he could not catch Wu Ling, any goose would make him a good dinner. He splashed through the water toward the island until he reached it.

Moments later, Chou was flying after Wu Ling and the other geese. He could hardly see or hear them at first. But he did not let this discourage him. Calling upon every last bit of his strength, he forged ahead.

Each flap of his wings brought him closer. The wedge of geese slowly grew bigger. The honking grew louder. At last Chou found himself flying beside Wu Ling.

"I'm tired of our silly game," he cried. "Come back with me to our willow tree."

Before Wu Ling could answer, something stung Chou's right wing. He sank toward the ground.

A hunter had shot him. Wu Ling flew down beside Chou, place his left wing under Chou's smashed right wing, and together they fluttered down to the edge of the forest.

The hunter ran toward them.

"Fly away," Chou urged Wu Ling. "Save yourself. Fly! Fly!"

"I wont' desert you," cried Wu Ling. And with a mighty roar, he changed into a lion.

Tangram- Lion
The hunter raised his bow. Wu Ling sprang toward him and knocked the bow from his hand. The hunter fled, leaving his bow behind.

Wu Ling and Chou returned to their fox shapes. And Wu Ling helped Chou to his den, where he took care of him until he was mended.

"Did they ever play that game again?" asked Little Soo.

"Many times," said her grandfather. "But they were very, very careful,"

"That was a good story," said Little Soo. "Let's do another."

Grandfather arranged his seven tangram pieces.

"Is this story going to be about a man?" asked Little Soo.

"Yes, said her grandfather. "he's old and he's tired. He wants to sit under a tree and rest awhile."

Tangram- Grandfather Tang
"Is he a grandfather like you?" asked Little Soo. "Yes," said her grandfather just like me." Little Soo arranged the seven pieces of her tangram beside her grandfather's.

Tangram- Little Soo
"Is that a little girl?" he asked.

"Yes, said Little Soo. "Just like me. She'll sit and rest beside the man."

"That will make him very happy," said Grandfather Tang. "And now, Little Soo, what will we do?"

"We'll sit and rest together until Mother calls us for supper," said Little Soo.

"That will make me very happy," said her grandfather.

Et Voilá!
Try to make your own stories with the 7 Tans!


Instant facts- Just add water 31

The bicycle as we know it today – with two wheels of the same size – looks almost exactly the same as one from 1900.

Friday, January 20, 2012

Instant facts- Just add water 30

The domain name was registered on Valentines Day (February 14, 2005)

Thursday, January 19, 2012

Instant facts- Just add water 29

Around 2000 different types of plants are used by humans to make food.

Wednesday, January 18, 2012

Looking for the gravity center in a soda can

Another trick from the video. A razão pela qual a lata fica "em pé" é exactamente a mesma da dada no caso dos garfos, é uma questão de centro de gravidade.

What we need:
  • 1 soda can,
  • water.
How to:
  1. Fill 1/3 of the can with water;
  2. Place the can on the table with a 40º degrees inclination; 
  3. Try to balance it, you will be able to balance the can in a "falling position", if the can starts to rotate over the bottom let it rotate until it stops.
What happens?
There is a position where the can stands in a strange equilibrium.

Exactly for the same reason the forks found the balance here.
Try this with other recipients and/or cans.

Et voilá!


Looking for the Gravity Center

Yet on this video, the forks trick.

What we need:

  • 2 forks alike,
  • 1 toothpick or skewer.
How to:
  1. Place the forks  like the illusionist in the movie, otherwise you will never make it;
  2. Place the  toothpick or skewer between the fork tines, in the middle and up;
  3. Place our finger on the toothpick tip, like in the video
  4. Try to do the same you did on step 3 placing your finger on the opposite side.
NOTE: We didn't have access to a toothpick thick enough to fit perfectly the forks, so we used tape to hold them one to another. This doesn't affect the demonstration.

What happens?
In step3 the forks stay on the tip of your finger in a "falling" position.
In the step4 the forks moves in an attempt to find its balance.

Before anything else we need to understand 2 things:
  • Center of mass - this position is defined mathematically. It's the result of an external force acting on the object. This center of mass isn’t necessarily the geometric center of the object.
  • Center of gravity, it’s the point which we must apply the force to balance the force of gravity. Imagine a tray, if we want to balance it with just one finger, and assuming the center of mass is at the geometric center, center of gravity is exactly the point where we must apply the force to keep it still but suspended in the air without rotate or fall.

So, what determines the balance of a body is called the location of the center of gravity, in other words the "point of application" of the gravitational force (weight).

Returning to the forks, they are definitely in equilibrium, it's indifferent if we use a finger or any other object (for purposes of this magic trick we will say that our finger has paranormal abilities, but in fact physics takes care of it). Where is the center of gravity? The center of gravity is somewhere between the extremities of the forks.

Some daily examples:

  • The equilibrist uses the rod to keep the center of gravity at place, it's important that the center of gravity is above the wire; - The stick helps to restore balance.
  • When you grab a large/heavy object automatically you change your body position. This is due to the fact that our body has a fixed center of gravity, when you add more weight/volume to the equation, the body has to readjust the new center of gravity.- Body may assume incorrect positions when transporting heavy loads. 
  • Notice that, when a baby is learning to walk, often falls forward or sideways, to us this doesn't make much sense, but the baby is trying to learn where is his balance.- The balance is learned.
  • Finally, notice Cristiano Ronaldo, during the games, bends his knees and sudden change his direction, without falling, why? Among other things, because when he bends his knees he makes his center of gravity lower so he can get more balance. The same goes for race cars. A car with a lower chassis is a faster car, why? Because the center of gravity is lower and the car becomes more stable in tight turns and can therefore go faster. - lowering the center of gravity increases the balance.

Try to find other systems in weird balances.

Et voila!
Balance in your fingertips!


      Carful with the dishes

      From here
      At first sight looks easy, but a closer look take us wondering "how did he do that?".
      Please do not try this without adult supervision


      • The cloth must be small,
      • The plates must be placed 1 or 2 in away from the table edge,
      • Don't use plastic dishes, they are too light,
      • A smooth table will make your task easier.
      What we need:
      • a table,
      • a table cloth,
      • plates, cups ad tableware, try just one plate at first.... then add more stuff to the table
      How to:
      1. Follow the NOTES advices;
      2. Grab the table cloth with both hands;
      3. Pull it in just in a single fast movement in the floor direction, this step may require training.
      What happens?
      You pull the table cloth and all the plates remain on the table.


      All the objects on the table are in rest.
      All objects in rest need to overcome inertia in order to move.
      We already talked about inertia. The Principle of Inertia is the first law of Newton and says:
      "All bodies remain in their state of rest or uniform rectilinear motion, unless they are forced to change its state by influence of external forces"
      In simple words, the Newton's First Law says: "If something is moving or stopped, will remain in motion or stopped unless something disturbs the system."

      Basically what happens is that the objects are at rest on the table, if the table cloth is soft enough, if the board is regular and the pull is fast and clean the dishes will stir but will not fall.  The energy we give to the system table+objects+table cloth it's not enough to make the objects to fall.

      Et voilá!
      Don't do this at home!


        Instant facts- Just add water 28

        Louis Pasteur (1822- 1895) is buried in a tomb inside his own Instiute - Pasteur Institute founded in 1888 in Paris.

        Tuesday, January 17, 2012

        Instant facts- Just add water 27

        A Praying Mantis has a average life span in the wild of 12 months
        in National Geographic online

        Monday, January 16, 2012

        Instant facts- Just add water 26

        More than 10,000 known ant species occur around the world.
        in National Geographic online

        Saturday, January 14, 2012

        Bernoulli demonstration with a ping pong ball and a hairdryer

        Daniel Bernoulli was born in the Netherlands on February 8, 1700; he was a mathematician and physicist. In 1738 he published one of his most famous works: Hydrodynamica.

        Bernoulli's theorem states that an increase in the speed of the fluid occurs simultaneously with a decrease in pressure. In other words the velocity increases pressure decreases.

        Bernoulli's Theorem allows us to understand why planes can fly for example.

        We can explain this theorem using available materials and very simple demonstrations.

        What we need:
        • hairdryer;
        • ping pong ball;
        • cardboard tube, look in kitchen for paper towels rolls.
        How to:

        1. Turn on the dryer;
        2. Select the maximum speed and the lower temperature;
        3. Point the dryer up;
        4. Place the ball in the airflow, find the equilibrium, this may require some practice;
        5. When the ball is stable in the air, approach the tube from the dryer.
        What happens?
        The ball is sucked through the tube and comes out the other side. 

        Because the force balance is disturbed.

        Bernoulli theorem states that a liquid or a gas lose pressure when its velocity increases. In this demonstration the ball was steady in a cold air flow, the air was moving and the pressure was low. The air exits the dryer and moves around the ball. This system is in equilibrium and the pressure is kept constant. This allows the ball to be in place.
        When we add the tube to the system, we force the air to pass thru it, and therefore circulating in a confined space. This leads to the increase of air velocity, and consequently to the pressure decrease inside the tube, and that’s why the ball is sucked in the tube, in an attempt to recover the system balance.

        Check out the video:

        Et voilá!
        Pure physics!


        Connolly, Sean, 2008 "The book of totally irresponsible science", Workman Publishing, NY

        Homemade instruments- rice shaker

        All the restless children love "to do music", most of the time it's more noise than melody, but it is also true that's an important component of development.

        Let's see how to build a rice shaker.

        What we need:
        • empty can,
        • balloons, ideally busted,
        • rubber bands,
        • rice,
        • glue,
        • old newspaper and magazines,
        • tape,
        • pliers.
        How to:
        1. Wash the can, and dry it;
        2. Remove the glue residues;
        3. With the pliers turn inside the cutting edges of the can, this is a very simple procedure that avoids accidents later;
        4. Cover the ca with the paper, fix them with the tape, apply them at will, overlap, stick them together, leave this task to your restless, they usually achieve fantastic results;
        5. Let it dry, at least for 4h;
        6. Place half a cup of rice inside the can;
        7. Stretch the balloon with the hands;
        8. Use it to close the top of the can, make sure the top of the can is closed;
        9. Use the duct tape and rubber bands to help secure the balloon;
        10. Repeat the procedure 2 or 3 times with different balloons, the top of the can must be tightly closed.
        • You can paint the can after you glue the paper, use acrylic paint.
        • Different seeds/ grains/ dried leguminous make different sounds, try to do several cans.

        Et voilá!
        Music in a can.


        Plastic bottle moneybox (PET)

        Transform a plastic bottle into a piggy bank.

        What we need:
        • plastic PET bottle with cap,
        • 4 PET bottle caps or 4 cork wine stoppers,
        • acrylic paint,
        • cardboards,
        • double tape,
        • exact-O knife or scissors;
        • color markers;
        • other materials you want to reuse, as buttons for the eyes.
        How to:
        1. Remove all the stickers and labels from the bottle;
        2. Wash it with running water;
        3. Let it dry completely;
        4. Close the bottle and place it in horizontal position;
        5. With the marker draw the place where you want to make the hole for the coins;
        6. Use the scissors, or the exact-O knife to open the hole, this requires adult supervision;
        7. Glue the 4 caps o the bottle, they must pretend they are the pig feet but most of all they must keep the bottle steady;
        8. Now its time to get creative ad to make your piggy bank one of the kind, paint it and decorate it at will, reusing materials is a good option.
        • Use hot glue for the feet;
        • Use double sided tape to glue the cardboard;
        • If you paint the bottle paint it first with white;
        • The normal acrylic paint comes off the plastic after a while.
        Et Voilá!

        Allways the same side down- Electrical charges

        This is a very simple demonstration, with an explanation beyond the obvious. This fully works using available materials. 

        What we need:
        • cooking oil,
        • water,
        • a small glass,
        • cardboard,
        • a charcoal,
        • a puncher.
        How to:
        1. Fill half glass with water;
        2. Fill the other half with oil;
        3. Paint the cardboard with the charcoal, saturate the cardboard with the pencil as much as you can;
        4. Punch little circles on the painted area;
        5. Place the circles in the cup.
        What happens?
        The painted side always faces the oil.

        Graphite is a good conductor, and has negative polarity. The polarity of the graphite repels water so that the painted face is always facing the oil.

        Transform this demonstration in an experiment

        1. Try other types of oil;
        2. Try mixing salt or sugar in water;
        3. Paint the cardboard with your colored pencils, or crayons ...
        Record the observations, the falling speed of the balls and the number of times the balls fall into another position.

        NOTE: You can only study one variable at a time, otherwise you will not be able to establish the cause / effect.

        Et Voilá!
        Electric charges at work

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