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.

Wednesday, December 28, 2011

Counterintuitive Demonstration- Ciment rice

Today we are going to see a weird demonstration. Not a weird "weird" demonstration, but let's say it defies logic, with this experiment we want to show that, in order to think science, we need to clear our mind from some preconceived ideas. This is a real problem, often we do not place certain questions because we are sure of the answers, and this is bad science.

NOTE: This demonstration needs adult supervision.

What we need:
  • rice,
  • a plastic jar, we used a baby's bottle,
  • a knife,
  • resistant surface, like a kitchen counter,
  • patience and a broom.
How to:
  1. Fill the jar with rice;
  2. Plunge the knife "halfway" into the rice a few times; it's easier if you lean the jar 5 or 6º;
  3. Fill the jar again, repeat the process;
  4. With a fast and clean hit, jab the knife up to the hilt into the rice, be careful with your hands, an adult must supervise this step;
  5. Pull the knife straight up.
What happens?
The jar comes up with the knife.

The force of pressure can overcome the force of gravity.
The preliminary stabs made rice grains to settle in close to each other. Thousands of rice grains surrounded the knife when we plunged it halfway, after each stab, the grains got closer and closer.
In the last step we pulled the knife straight up into the settled in rice, the knife is sharp enough to be jabbed into this network of pressure, but at same time the rice settles back in from all sides to hold the knife in place.

Please Note:
It's normal if you have to repeat several times the steps above until you have success. Persistence is the key; you may try to change the knife or the container.

This demonstration can be an experiment, or a science fair project:
  1. Change the container, different volume, high...;
  2. Change the knife width, length, or material....;
  3. Change the rice; use other grains, sugar, salt, sesame seeds, sand...
Record the weights of the containers with and without rice, record the width / length of the knife and all the variables of your essay.

Et Voilá!


Connolly, Sean, "The book of totally irresponsible science", 2008

Cleanning pennies

A penny is a penny, but we can make them shiny and clean with a little help of chemistry. This is another demonstration using vinegar.

NOTE: Don’t use this method to clean collection coins, this can damage the coin. If you have collector coins or valuable items ask a specialist how to clean them.

What we need:

  • pennies,
  • vinegar,
  • salt,
  • a jar, with lid
  • tablespoon,
  • paper napkin.
How to:
  1. Mix 2inches of vinegar with 1 tablespoon of salt in the flask;
  2. Close the flask;
  3. Stir to dissolve the salt;
  4. Open the flask and place 2 or 3 coins inside;
  5. Close it again;
  6. Wait 1 or 2 minutes;
  7. Open and remove the coins, be careful with vinegar smell;
  8. Place the coins in the paper napkin to dry;
What happens?
The coins become clean and shiny
The solution we made with the salt and the vinegar released the residues of the coins, and the coins become clean as new.
This residue is copper oxide, this oxide reacts with the vinegar (acetic acid) and the reaction product remains suspended on vinegar.

Et Voilá!
Clean as new


    Friday, December 16, 2011

    Instant facts- Just add water 15

    United Nations have 193 Nations, US recognize only 195 countries, but in fact there are 196 countries that meet "requirements of independent country or state status".

    Thursday, December 15, 2011

    Instant facts- Just add water 14

    East Timor became the first new sovereign state of the 21st century on May 20, 2002.
    in wikipedia

    Wednesday, December 14, 2011

    Instant facts- Just add water 13

    The common abbreviation for Christmas to Xmas is derived from the Greek alphabet. X is letter Chi, which is the first letter of Christ's name in the Greek alphabet.

    Tuesday, December 13, 2011

    DIY Pendant with beach stones

    Another DIY project for the Summer.
    Use your restless beach stone collection to make beautiful and personalized pendants. You can use them with chain-keys, necklaces or bracelets. You also can paint some lucky charms like the "Evil Eye"- in last picture-, this amulet will protect everyone who use it against the evil eye .
    Or you can simply ask your restless to paint the stones as he wishes.

    We will need:
    • alcohol,
    • little stones from the beach,
    • thin wire,
    • pliers,
    • pencil,
    • acrylic paints,
    • varnish.
    How to:
    1. Chose your stone, to paint evil eye the stone must be small, round and plain. try to chose the small ones, you will not want to use heavy weight around your neck;
    2. Clean the stone with tap water and alcohol to clean the salt, the sand and any other residue;
    3. Draw on the stone what you want to paint;
    4. Next paint all the stone with a light color, (white if possible);
    5. Next color your draw with the other colors, first the light ones;
    6. You must resist painting the details, Those will be the last thing to paint;
    7. Wait for 4h, paint must dry;
    8. Varnish and wait another 4h;
    9. Now you have 2 choices:
      1. Use the wire and make a cage for the stone: Use the pliers and curl the wire around the stone. The stone must be trapped but not "glued" to the cage. When you finish make a double ring and super glue the 2 turns of the ring.
      2. Make a double ring with the wire: Make a double ring with the pliers but don’t cut the ends, super glue the end tips to back of the stone.
    10. You can use this in many was: in a bracelet, in a necklace, in key chains...
    NOTE THIS:  If you chose to paint the evil eye- in the image-you must know that some people believe that a blue looking towards to us brings bad luck (although the blue-eyed person is good and virtuous), that’s the reason the most common color in evil eyes is the blue (they take away the bad luck)

    Et voilá!
    Another great use for beach stones


    DIY Christmas Project - EVA Santa Claus ornaments

    This week the invited super restless mind is Quiane with a Santa Claus mold. Use it to do some ornaments to your Christmas tree, use EVA or Felt.

    Source: Pais Natal para a árvore- em Feltro ou em EVA.

    Et Voilá!


    Instant facts- Just add water 12

    There are over 350 different breeds of horses and ponies.

    Monday, December 12, 2011

    Underwater candle

    We learn here how water can work as a fantastic magical element in a illusion trick. Today we will see another heat transfer experiment, this time between water and wax.

    We will need:
    • 2 candles, identical
    • 2 tall bowls, higher then the candles and identical,
    • match box, or a cigarette lighter,
    • water, enough to fill the bowls.
    How to:
    1. Chose a safe spot for the bowls. They will stay there for a while;
    2. Place the candles inside;
    3. Fill one bowl with water, leave about 1 in of the candle above the water level ;
    4. Don't fill the second bowl;
    5. Light both candles, this is an adult task;
    6. Wait several minutes;
    7. Let the wicks burn slow, The candle in the bowl with water will reach the water level;
    8. Let it burn for a bit more;
    9. Observe.
    The candle in the empty bowl burns normally, as the wick is consumed the wax melt and the candle begins to get smaller.

    The candle in the bowl with water burn normally until the wax reach the water level, here, or maybe a few mm before, the candle forms a "funnel", preventing water to contact with the wick, and the candle continues to burn for some time.

    Both candles are consumed by the wick flame; if the candles are identical you can observe they burn at same velocity, until the water is placed in the equation.
    Everything changes with the water. The candle is consumed because the wax is heated by the wick flame and as consequence the wax melts.

    When we light up a candle we expect it to melt, but when we place it "under water" we expect the flame to go out.
    But the true is: we can observe the candle burning underwater, it looks like the candle has a survival instinct, just like the balloon, and exactly for the same reason that the balloon doesn’t burst, the candle still burning, and we can see the formation of a "funnel" like a hole, surrounded by wax thin walls, protecting the wick from water.

    This happens because the water is a good heat absorber; the heat necessary to raise water temperature by 1 degree is very high.
    When the wick transfers the heat to the wax, the wax transfer it to the water, this allows the wax in contact with water to remain cold, and therefore solid.
    This system is only in equilibrium for a few sec, or maybe a few minutes, but eventually the water will find its way, even because the walls will eventually collapse with the water pressure (weight) the water comes in and the candle sinks.

    This is a demonstration, you can transform this in a experiment or science fair project:
    • Use diferent candle types (form, color, thickness, height) which of the candles keeps water away for longer?
    • Vary water temperature; this helps the candle to stay lit for longer?
    Keep a record of your data

    Et voilá!
    Sometimes things may defy common sense


    Decorated candle with beach stones

    Another good application to your restless shell/stones collection is to do some candles. Doing candles can be a highly specialized task but it can be transformed in a very rudimentary task, anyway it's fun. 

    To this DIY project you can buy a white and plain candle, if you wish
    With this project you can recycle those annoying little crayons your restless keeps in his pencil box.

    We will need:

    • candle wax,
    • candle-wick,
    • old crayons,
    • beach stones, tiny
    • shells,
    • an old pot or metal box, the box will be trashed after this, you can use a metal milk powder box for example
    • Molds, the plastic yogurt cups work well they aren't the ideal material but they easy to find,
    • Wooden sticks, you can use clothes pins.
    How to:
    1. Wash and clean the yogurt cups very well;
    2. Cut the candle-wick with the cup height plus 2in;
    3. Chose a tiny, really tiny, stone to work as weight to candle-wick;
    4. Tie the stone to the wick.
    5. Tie the wooden stick to the other candle-wick end, the wick must be tied in the middle of stick;
    6. Place this “stick+wick+stone” set in the yogurt cup,
    7. The wick must be stretched, if needed adjust the knot on the stick;
    8. Place this cup in a metallic tray;
    9. Put the wax into the metal box and take it to the stove fire, don't use to much wax at the same time;
    10. Wait until the wax is pasty;
    11. Chose your favorite crayon color and chip it into the wax, keep the heat down during this process, this avoid the wax to become dark;
    12. Let the chips to dissolve and turn off the heat;
    13. Wait a few moments to cool the wax a little, remember you are using plastic yogurt cups and if the wax boil the cup will melt almost immediately, that’s why we use the metallic tray, to avoid accidents,
    14. Fill 1/4 of the cup with wax; place some stones against the mold wall;
    15. Place the wick on the center and far from the stones;
    16. Let it cool;
    17. Melt the wax again, you can chose to use another color, repeat the mix and the cool steps;
    18. Fill the cup at 1/2, place the stones, adjust the wick, and let it cool;
    19. Fill the rest of the cup with wax;
    20. Leave it to cool for 24hours;
    21. With the exact-O knife unmold the candle.
    Et voilá!
    Original candles you can use as you wish


    Floating grape- density matters

    This is another demonstration of density, your restless will love this floating grapes.

    Density is what does float in the air, ice cubes float on drinks and stones "drop dead" in the bottom of the lake.
    We are going to make a grape to float on a glass with water.

    What we need:

    • 3 transparent cups,
    • tape,
    • pen,
    • measuring cup,
    • water,
    • sugar,
    • 3 grapes,
    • tablespoon,
    • paper sheet.
    How to:
    1. With the pen, the paper and the tape, make 3 labels for the 3 cups- Cup1 Cup2 Cup3;
    2. Fill the measuring cup with water;
    3. Add sugar until the solution is saturated, it will be saturated when some of the sugar, not many, remains on bottom, even after you mix it well with the spoon;
    4. Fill the Cup1 with tap water;
    5. Place a grape inside, what happens?;
    6. Fill the Cup2 with the sugar solution;
    7. Place another grape on the cup, what happens?;
    8. Now, fill 1/2 of the Cup3 with the sugar solution;
    9. With careful fill the rest of the Cup3 with tap water. The best way to do this is to use a spoon. Place it inside the cup, without touching the sugar solution, let the water drain along the spoon, as we saw here.
    10. Place a grape inside the cup. What happens now?

    The grape is denser then the water, so it sinks.
    The sugar solution is denser then grape, so the grape floats. But the sugar water is denser then the tap water, when we place this 2 liquids in layers, the grape its trapped between the layers and floats.

    If you prepare the sugar solution several hours before use it, the difference between the 2 are imperceptible, and really looks "a kind of magic";

    Make this a experiment, try to use salt or substitute grapes for raisins... What happened? Keep your results in a log.

    Et Voilá!
    It's a kind of magic...


    Photo in a lamp

    Look to an object and see beyond the obvious is a good exercise. Our brain must be trained to do this. A good way to train this is to reuse objects; sometimes we trash materials that can be something else. This thinking promotes recycling and stimulates the reuse, encouraging energy saving with the waste reduction.

    Old lamps are good objects to reuse, we can pain them, we can fill them with color sand, make a jar... But there is a problem with lamps, open it, it's needed some training to open a lamp without broken it

    What we need:

    • pliers,
    • screwdriver,
    • lamp, Broken lamp to reuse
    • a towel, rag,
    • wire,
    • wood block,
    • sandpaper,
    • acrylic paint,
    • varnish,
    • mini clothespin,
    • glue, hot glue works better,
    • lamp socket, you can buy it in any hardware store,
    • screws, for the socket ,
    • rubber feet, or felt;
    • a photo, small enough to fit inside the lamp.
    How to:
    1. Sand the wood block;
    2. Paint it with the acrylic paint, remember the bottom will be hidden and the top will be partially covered with the socket;
    3. Let i dry for about 24h;
    4. Varnish;
    5. Let t dry again;
    6. Glue the rubber feet on the bottom;
    First phase is done, lets take a look on the lamp, this must be done by an adult
    1. Place the lamp on the towel, and with the pliers, remove the metallic tip of the screw of the lamp. Just the tip, don’t use to many pressure on the lamp, grab the screw with your hand and the metallic tip with the pliers,  rotate steadily, be careful with your fingers, child must be away from you while you are doing this.
    2. When we pull the tip with the pliers all lamp content is dragged out;
    3. Confirm the lamp is really empty;
    4. Wash the lamp with tap water;
    5. Let it dry.
    The lamp is ready, lets place the picture inside: 
    1. Screw the lamp socket to the wood block;
    2. Cut a piece of wire, about 2 and half times the height of the lamp;
    3. With the pliers roll up the wire like the one on the image, when you finish this twisted wire must fit inside the lamp.
    4. Glue the mini clothespin to the other end of the wire, upside down;
    5. Bend the wire end, the curly section will support the picture, like feet, and the mini clothespin will work as a pin;
    6. If the wire is too big cut it now;
    7. Place the wire inside the lamp, remember to do the last adjustments to it, size and position;
    8. Pin the Photo to the clothespin;
    9. With careful and patience, place the set "wire + clothespin + photo" inside the lamp
    10. If necessary use hot glue to fix the wire to the lamp socket.
    11. Screw the lamp.

    Et voilá!
    A photogenic paperweight 



    Friday, December 9, 2011

    Instant facts- Just add water 11

    Nearly 60 million Christmas trees are grown each year in Europe.

    Wednesday, December 7, 2011

    Instant facts- Just add water 10

    Elephants sleep standing up during non-REM sleep, but lie down for REM sleep.

    Tuesday, December 6, 2011

    Rainbow in a jar- density column

    Sometimes the simplest things are the funniest. This demonstration shows multicolored layers in a jar without using much "chemistry". The final result is called "density column" because it allow us to make a pile with liquids with different densities, like we saw here.

    In this project we are going to use sugar solutions with different concentrations. Those will form layers, the less dense (more diluted) at the top, the most dense (concentrated) at the bottom of the glass

    We will need:
    • sugar,
    • water,
    • food coloring,
    • tablespoon,
    • 5 transparent plastic cups, you can use flasks or glass cups but they must be transparent.
    How to:
    • Align the 5 cups on the table;
    • Add 1 tablespoon of sugar in the first glass, 2 on the second, 3 on the  third... and so on, leave the fifth empty for now;
    • Add 3 water tablespoons (about 45 ml) to the first 4 cups;
    • Mix, homogenize the solution, if the sugar does not dissolve completely in any of the glasses add another tablespoon of water to all the glasses,
    • Add 2-3 drops of red food coloring first glass, use yellow on the second, green on the third, and blue on the fourth;
    • Mix again;
    • Now let’s set up our rainbow. First the denser solution (more concentrated), in this demonstration is the blue with 4 sugar tablespoons. Fill 1/4 of the fifth glass with the blue solution;
    • Carefully place the green solution on top of blue. The best way to do this is to put the tablespoon inside the glass, without touching the blue solution, and allow the green solution to flow along the spoon;   
    • Repeat the procedure to all the solution in this order: Blue (done), Green (done), Yellow and Red. Each solution must occupy 1/4 of the glass.
    If you don't succeed at the first try don't quit, try again. It’s hard to do it right without training.
    There is no problem if you drink it, its only sugar water.

    To make this demonstration a experiment try:
    • To use flavored food coloring, what happens?
    • To use water with different temperatures? Does this have any influence in the experience? How? Be careful with burns.
    •  What happens if we disturb the equilibrium of the layers? try to use a toothpick and touch 2 or more layers with it.
    Et Voilá!
    Multicolored drinks, like witch potions.


    Christmas Origami star- tutorial

    We already did the tree and some ornaments, like Christmas balls, now its time to do the Christmas Star.

    What we need:
    an old magazine, 5 sheets for each star,

    How to:

    1. Fold the sheet in half and open it again;

    2 Fold the 2 up paper ends inside, like the picture;

    3. Fold the triangle down;

    4. Flip the paper horizontally;

    5. Repeat step number 2;

     6. Fold it again, like you are doing a second triangle; now it looks like a paper airplane;

    7. Flip it again horizontally;

    8. Fold up the 2 little ends on the bottom;

    9. Now make a thin roll with the paper up to the end of the paper;

    10. When you reach the top flatten the paper with your fingers, now you must have something like the picture, this is one of the five star tips;

    11. Each star have 5 tips

    12. Fit the points as shown, first the back;

    13. Then the front;

    14. Repeat the procedure until all the tips are fit. this is the final result;

    15. This is what it looks like on the back.

    You can paint it as you wish, use glitter to make it shine!

    Et voilá!
    Without the star the tree is not a Christmas tree!


    Instant facts- Just add water 10

    Every ton of mixed paper recycled can save the energy equivalent of 165 gallons of gasoline
    in Municipal Solid Waste Generation, Recycling, and Disposal in the United States: Facts and Figures for 2010- United States Environmental Protection Agency

    Monday, December 5, 2011

    Water properties- Adhesion and Cohesion

    If we talk about water we must refer cohesion and adhesion.
    We already talk about another water properties the surface tension, but without the first two the triad wouldn’t be complete.
    Most of the times water molecules are attracted to each other, in this case we are dealing with cohesion, on the other hand, if water molecules are attracted to other materials then we are dealing with adhesion.

    What makes it possible?
    As we said in other articles water molecules are made by 2 H atoms and one O atom, this gives water molecule a neutral charge, but its structure allows the water molecule to establish hydrogen bonds between H atoms from different molecules, this bonds make molecules closer from each other, that phenomenon is called cohesion. If the attraction between the H atoms is weaker then the attraction between water molecules and other material molecules surrounding, the water molecules will bond to this surrounding material instead, we call this adhesion.

    All hydrophobic surfaces will repels water, this means the water molecules are not attracted to it and they form drops, this is cohesion, like wax paper or any waxed surface. Like the shower after being cleaned with specific soap, in fact a thin hydrophobic layer is formed to repel water- Cohesion.
    It is also due to cohesion that the rain falls in droplets rather than molecules, otherwise we would call rain to something completely different

    When water molecules are attracted to other surrounding molecules the phenomenon is called adhesion. We saw it here, remember? The water "climbed" the paper against gravity, this happened because water molecules were strongly attracted by cellulose molecules on the paper, this attraction was stronger then the attraction between H2O molecules.

    Note this phenomenon only occur because one of the forces is stronger then the other.

    In short:
    Cohesion- when attraction forces between water molecules are stronger then the attraction forces between water and surrounding material molecules.
    Adhesion- when attraction forces between water molecules are weaker then the attraction forces between water and surrounding material molecules.

    The following demonstration its very simple and works very well to show cohesion

    What we need:
    1. 2 styrofoam cups,
    2. water,
    3. sharp pencil or any sharp object like a nail,
    4. a bowl.
    How to:
    1. Choose an appropriate location;
    2. With the pencil make two holes in the first cup, as close as possible but not touching, don't make them too large;
    3. Fill the second cup with water;
    4. Hold the punched cup above the bowl;
    5. Pour the water from the second cup into the first;
    6. The water should start to fall through the holes you made with the pencil;
    7. Quickly, "hold" the two "threads" of water with your fingers (thumb and index).
    The 2 "threads" become one.

    The water molecules are attracted to each other.

    Please note:
    • Probably you will not make it work at first time, try again.
    • If you are lucky you will achieve the optimal distance between the holes, in that scenario you will not need to use your fingers, the "threads" will become one naturally.


    Et voilá!
    Don’t get wet!
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