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.

Thursday, January 24, 2013

Valentine's Restless Ideas

Valentine's Restless Ideas just for you
Et voilá!

Monday, January 21, 2013

Super restless bottle animals

I found his idea here in Banana Craft blog , and you can find the step by step here.

This craft recycle PET bottles, and the result is a lot of color and fun animals.

What we need:
  • PET bottles, The step by step instruction use 600ml bootles, but you can use any,
  • hot glue;
  • soft paper;
  • EVA;
  • felt;
  • googly eyes, or small buttons;
  • PET caps, yogurt or soda;
  • rice, you can use sand or beans;
  • paint, spray works best;
I think the step by step is very good, so I will leave you with the final result.

Et Voilá!
Fun fun fun!


Frame with yogurt recicled caps

This is fun, colorful, easy and pretty.

What we need:
  • yogurt caps, all of the same kind, we used 56,
  • thin wire,
  • pliers,
  • small drill, like a  drummel, use glue if you prefer;
  • acrylic paint;
  • varnish
  • soft brush 
  • swabs.
How to:
  1. Wash the caps;
  2. Let them dry;
  3. Place the caps on the table and see the format you want to give to your frame;
  4. Take 2 caps;
  5. Use the drill to open a small hole on each cap side wall;  
  6. Use the pliers to cut the wire (about 6cm);
  7. Fold the wire in half, like a clamp;
  8. Pass one end through the holes, pull the clamp up and tighten down with pliers; 
  9. With your fingers push wire ends down, to the opposite direction, and then again with the pliers tight it;
  10. Repeat the operation for all the caps; 
  11. You can do line by line, then link the several lines, or you can do it in spiral, like the picture shows;
  12. Before using the drill mark the spot with a pen;
  13. If you are using glue is much easier, just apply the glue and lean the caps.
  14. When you are done clean all the surface with alcohol;
  15. Let it dry;
  16. Use your imagination to paint it, we made some silly faces;
  17. Use varnish to finish the job;
  18. Use the swab to paint the eyes;

Et Voilá!
Everyone can be an artist!


Grow Stalactites with a string

Mira d'Aire
a cylindrical mass of calcium carbonate hanging from the roof of a limestone cave: formed by precipitation from continually dripping water

a cylindrical mass of calcium carbonate projecting upwards from the floor of a limestone cave: formed by precipitation from continually dripping water


Let´s try to do our own stalactites and stalagmites, with water and salt.
At first sight may look simple and easy, but in fact is a lot difficult because it will depend on a lot of variables.

What we need:
    • Epsom salts,
    • water,
    • 2 identical glasses,
    • string or paper towel,
    • 2 paper-clips or weights,
    • spoon,
    • bowl or pot,
    • a good place to leave the glasses siting for a few days
    How to:
    1. Fill a glass twice with water and dump it in the pot,
    2. Add 1 Epsom table spoon;
    3. Mix;
    4. Repeat again and again until the solution is saturated;
    5. Heat the heat the pot on a stove, caution!
    6. Add more salt and keep stirring, hot water can  dissolve more salt, do not boil the water;
    7. Split the water for the 2 glasses, try to be the more exact as you can;
    8. Find the location where they will sit for the next few days...;
    9. Leave a 3 or 4 inches between the glasses;
    10. Cut a string big enough to cover the distance between the glasses and hang down to the bottom of both glass;
    11. Tie the paper clips in both string ends;
    12. Place each one on a glass;
    13. Wait, observe ad take notes.
    What happens?
    After a few days we will notice a little stalactite on the string.
    With a bit of luck you will be able to see a stalagmite too.

    The water travels through the string and the salt goes with it. While the path is vertical the salt "plays along" with water, but when the path becomes vertical, the gravity wins and the saltwater is pulled down. The water trickle and leaves the salt behind on the string. With time the salt will form a  stalactite.
    If you are lucky and wait enough time you will be able to see the stalagmite formation, under the stalactite.

    This demonstration is not so easy as it seams.
    • You need a strong and concentrate solution of salt;
    • For better results immerse the string in the solution, before you place it between the glasses.
    • If the water is dripping very fast increase the distance between the cups, that will reduce the inclination angle.
    • Do not use a wood surface, it may damage the wood.
    A step further:
    • Use different strings;
    • Use other salts;
    • Use different concentration solutions;
    • Change one thing at time;
    • Register everything
    Dicionário de Mineralogia e geologia ilustrado

    Et voilá!
    Geology in the kitchen


    Build a Terrarium- Ecosystem inside a jar

    In National Geographic
    A terrarium is a completely self-sustaining ecosystem in a container that is designed to house small animals and plants under controlled conditions.

    The closed nature of a terrarium creates an environment easy to control, allowing the simulation of environments from desert to rain forest.
    In general it is made in a clear naked container, but can also be constructed in wood, for example.

    The top can be open or closed depending on the environment we want o recreate. When open it's protected with a net to prevent the "escape" and the entrance of living beings.

    How does it works?

    The plant resets the oxygen, the light is a source of energy, the water comes from moisture in the soil. As the dead leaves fall and decompose providing food for the soil.

    We can build a Terrarium, that's today proposal.

    What we need:
    • transparent glass container, with a wide opening,
    • small stones,
    • activated charcoal, you can buy it in a pet shop,
    • potting soil,
    • small sponge,
    • a net with a fine mesh 
    • canvas
    • moss and/or plants.
    How to:
    1. Chose what plant you want to use, they must be small and slow growth;
    2. Place the small stones in the container -terrarium;
    3. Spread a small amount of activated charcoal on the top of stones;
    4. Take a piece of canvas and make a small cut in the middle
    5. Cover the charcoal with the canvas;
    6. Place a sponge (with 3cm wide) in the canvas cut, this will take the moisture to the plants;
    7. Cover the all hing with soil; 
    8. Place the plants. Just like you will do it in the garden;
    9. Spray your plants with water;
    10. You can add o your garden some action figures;
    11. Close the Terrarium with the net;
    12. Wait to see if it works.
    At first the Terrarium will look fragile, but after a few days the ecosystem will start operating normally. It's normal if the first try fail, but don't give up, use different plants and different soil and try again.

    Et Voilá!
    Can you make it work?


    Floating pin

    Another demonstration. So simple but so interesting

    What we need:
    • straight pins,
    • water,
    • toilet paper,
    • bowl.
    How to:
    1. Fill the bowl with water;
    2. Wait a few seconds until the water stop moving;
    3. Can you place a straight pin floating in the water? Try it;
    4. What happened?
    5. Try a second pin.
    6. Place the pin on the top of  a piece of toilet paper;
    7. Place both things in the water, very carefully and gently
    8. Wait a few seconds.
    What happens?
    The paper sinks, the straight pint floats.


    Surface tension, that's the answer.

    When we place the pin in the water, without using the paper, it immediately sinks, its weight is too high for the area it occupies, ie is very dense.

    The paper, by contrast have much area for the weight, in fact it doesn't sink, actually it soaks, in other words water molecules fill the paper pores in it's porous structure and fill the voids in the web cellulose paper. this way the paper becomes heavier and sinks.

    Surface tension is responsible for what one might call "skin."

    The water surface is formed by a barrier of water molecules. This barrier is what allows insects to land on water, the soap bubbles to exist, and the pin does not sink.

    The first pin sinks because it doesn't start from a position of equilibrium and rest, unlike the second which is resting on the paper. The paper when sinks exerts sufficient force on the skin of the water to bend it but not to break it, and the pin floats.

    Et voilá!
    It's magic! No, it's science!


    Electric and bouncy pepper

    This is another version of the Jumping paper circles demonstration.
    Today we will use black pepper powder.
    What we need:
    • black pepper powder,
    • salt, 
    • wool cloth,
    • plastic fork or spoon,
    • plate.
    How to:
    1. Mix some pepper and salt in the plate,
    2. Mix well, use the fork to help you;
    3. Ask your restless to separate the salt from the pepper, humm... tricky uh?;
    4. Rub the fork in the cloth for 30-60sec;
    5. Approach the fork and the plate, keep the fork 2,5cm away from the plate.
    What happens?
    The pepper jumps to the fork, leaving salt behind 

    When you rub the fork with the cloth it becomes negatively charged, pepper is positively charged. That means, when you approach the fork the pepper is attracted to it, and "jumps".
    The salt is also negatively charged but is slightly heavier and it doesn't jump so easily. However, if you don't keep fork distance the salt will eventually jumps, thats because the electrical attraction overcomes the weight.

    See the movie:

    You can learn more about this here.

    Et voilá!
    Bouncy pepper!


    Jumping paper circles

    This is a classic! A electric balloon full of static electricity
    What we need:
    • 1 balloon,
    • 1 wool cloth, you can use your hair,
    • 1 paper hole puncher,
    • old paper, reuse some old paper.
    How to:
    1. Blow the balloon;
    2. Punch some holes in the paper, fold the paper several times before you use the puncher, that will give you more circles;
    3. Rub the balloon in your hair or in the cloth;
    4. Approach the balloon and the paper circles.
    What happens?
    The circles "jump and glue" to the balloon walls.


    Although this is a very simple and basic demonstration some of us never stop to think about what is really going on.
    The paper and the balloon are made of atoms. This atoms have a positive core surrounded by negative electrons, these move around the core.
    As we saw here several times everything tends towards an equilibrium and thats why almost everything that surround us is charged with a neutral charge. Is the same as saying that the sum of its charges is 0.

    Repulsion and/or attraction are only possible if the charges of both materials are different in sign. That means: repulsion and/or attraction are only possible when the objects have excess or lack of electrons and because of that have a negative or positive charge.

    When the balloon was rubbed it passed from a resting state to a excited state, and therefore electrically charged(in this case with excess negative charge).

    Why the balloon become charged? This was possible because the cloth and the balloon have different characteristics, one can receive electrons and the other can give them, despite they are both in a rest state to begin with. This means one is electronegative (easier to receive negative charges, balloon), and the other is electro-positive (easier to donate negative charge, hair or cloth), when two such materials are rubbed, negative charges migrate from one material to another, when are removed one is positively charged and the other negatively. If you use the hair you will find that it "will glue to the balloon."

    The paper was in a rest state, neutral charged. If that is true why does it jumps to the balloon wall?

    Yes, the paper was not charged.

    The attraction between a neutral charged material and another can be explained using the idea of electrical dipoles, a phenomenon commonly referred to as "charge separation" (in Figure). This separation happens when neutral object is subjected to the action of other electrical charges, in this case electrical charges of the balloon, thats why the paper circles "jump" to the balloon, attracted by the negative charges.

    Note: This electrical phenomenon only occurs between insulating materials, conductive materials do not have the ability to retain electric charges, as they seep through the material.

    A step further:

    • Change the rubbing time;
    • Change the friction material (cloths can try silk, cotton, wool ...);
    • Change the amount of air in the balloon.
    • Make a table to record your results.
    Do not forget the first rule: do not change more than one variable at a time.


    Et Voilá!
    So simple so scientific


    Floating lemmons, or not

    Peeled lemons sink, unpeeled lemons float.

    Why is that? Maybe the lemon peel acts like a lifebuoy, keeping the lemon above the water line.  

    What we need:
    • water,
    • small box or a glass container, transparent,
    • 1 lemon,
    • your lab notebook.
     How to:
    1. Fill the container with water, enough to float lemon;
    2. Place the lemon inside the container;
    3. Observe carefully what happens and record the results in your notebook;
    4. Remove the lemon from the water;
    5. Peel the lemon;
    6. Place it again on the water;
    7. Observe carefully what happens and record the results in your notebook.
    Attention: Ask an adult o handle the knife


    What happens?
    Peeled lemon sink, unpeeled lemon float.

    Notice that when the lemon was unpeeled it only sunk enough to stabilize its weight. In the picture you can see 1/4 of the lemon off water.

    This is due to, at least, two factors, density and porosity.

    Density, density depends on lemon weight and volume. But if we peel the lemon it becomes lighter nevertheless it sinks.

    Porosity, Lemon peel is extremely porous and when placed in water, the air is trapped in these pores and can not escape, this makes the lemon float. Just enough to compensate its weight.

    By simple observation we can see that the peel is made off two areas, a white and spongy one and a yellow and porous one. What if we separate this yellow and white areas?

    1. Place the lemon peel in the water. Does it float?
    2. Observe carefully what happens and record the results in your notebook;
    3. With a knife separate the yellow section from the white section;
    4. Try to place the white section in the container. Does it float?;
    5. Observe carefully what happens and record the results in your notebook;
    6. Now try with the yellow exterior section;
    7. Observe carefully what happens and record the results in your notebook.

    "The peel white section" floats! The yellow one sinks!
    If you look closer you can see that the white section is very spongy, and therefore very light, ie works as a buoy.

    In terms of evolution, in which only the fittest survive, we see this floating lemon as a competitive advantage, the fruits may fall from the tree, float in a water course and travel to other destinations and lands where their seeds can proliferate at will.

    A step further:
    • Use different citrus, like lime or orange.
    • Use different fruits like  apples or bananas.
    • In nature we can find different thicknesses of peels in lemons. Do the peel thickness affect the outcome?

    Et voilá!
    Archimedes in action.


    Thursday, January 17, 2013

    Food coloring chromatography

    QUESTION: Is it possible to separate the colors of a mixture of food colorings after they have been mixed?

    What we need:
    • coffee filters,
    • wooden skewer,
    • food coloring, yellow, green and blue,
    • 4 glass containers,
    • markers
    • 4 paper clips,water.
    How to:
    • Prepare the work area, chose a easy to clean zone in outside or in the kitchen, food coloring usually leave messy stains;
    • Identify the bottles, assign one or two letters each color, e.g. bottle Ye (yellow) Bl (blue) Gl (green) and Mix (mixed colors), or simply ABCD, write down in your notebook which is which.
    • Place 6 drops of yellow dye in the bottle Ye;
    • Dilute the food coloring with 30ml water;
    • Repeat this procedure for both blue and green dye;
    • In the last bottle (Mix) place 2 drops of each dye and diluted as usual;
    • Prepare the coffee filter, cut it in 4 identical strips;
    • Put a strip of paper in each bottle, as pictured;
    • Use the paper clips to keep the paper in place;
    • Wait until the dye reach the top of the paper, we wait 15min, may be more or less depends on the brand of the dyes.
    • After the dye reach the top of the paper remove it from the cup and put it on a horizontal surface;
    • Wait until it dries;
    • Observe the color patterns.
    What happens?
    The water climbed the paper and the food coloring dissolved on it formed patterns in the paper.
    In pictures you can see we used circle and strip paper, the results were exactly the same for the used colors.

    Chromatography is, as its name indicates, writing (spelling) colors (chrome) and is one of the main techniques that biochemists use to separate mixtures.

    First, before attempting to answer our question, it would be necessary to state three things:
    • The first is that we must have a control, in this experiment a bottle with solvent without the dye, to exclude any possible interference of anything, We have done it, but does not appear in pictures. We did not observe any color band in this “blank”.
    • The second is that the solutions were made with 6 drops of dye to 30 ml water, it’s possible you might get different results when using different trademarks and/or dilutions, so in science it is very important to control everything, even the brand of reagents.
    • And thirdly, we have to study the individually solution behavior so we can interpret the Mix results.

    Control: No bands or spots of any color.

    Green dye: Shows three colors, blue on top of the paper, a broadband green and a darker line on the base. We could observe a yellow band between the larger green band and the darker line at the base.
    In the label on the bottle we can read: ”Contains yellow dye and green dye“ that way is normal o have a green and a yellow band in the paper, but where did the dark line came from? A closer look give us the answer: the darker line is a dark blue zone. Blue? Yes blue. That’s because green is the mix of the blue and yellow color. 

    Yellow dye: the coffee filter paper was completely yellow. With a yellow zone more pronounced in paper, yellow is a primary color, and in the label doesn’t say anything about any addition of another type of dye.

    Blue dye: We can see that the filter has three distinct zones (note the small strip in the photo), back lit we see one of the area's violet (on the color wheel this is the result of mixing blue and magenta) the second zone is blue, and the third band is a second kind of  blue, lighter and more prevalent, one is cyan, and the other is an unknown color we would probably only find out for sure using more advanced analysis techniques.

    On the blue label we can read: “contains blue dye and E122”. What is this E122? The website describe it as a carmine food coloring, the presence of this E122 may explain the violet band observed at the base of the paper.

    After observing and interpreting individual results we will then look to the mix filter:

    One large blue zone followed by a green one. Between them we can see a faint yellow band, in the base we can’t see the violet line or brown stain which would be expected by the presence of green dye, instead we can observe a dark indistinguishable line. Back lit we can see some violet color, but nothing conclusive. Probably this phenomenon is due to the fact that the carmine E122 and the brown present at the bottom of the paper requires more time and /or longer/ different kind of  paper to separate and become visible.

    The answer to the above question is “Yes it is”. However it is necessary to improve the used technique.

    A step further:
    • Improve the separation method:
      • Using different dilutions;
      • Different filter papers;
      • Bigger filter papers;
    • See if you can see these bands, eventually even be surprised by other bands that become visible.

    Et voilá!
    A true experience!


    Dancing raisins in soda

    Will the CO2 released from a water with gas bottle be strong enough to take to the surface 6 raisins?

    What we need:
    • transparent glass,
    • water with gas, the strongest work best,
    • 6 raisins
    How to:
    1. Chose a easy to clean zone near the sink;
    2. Fill the glass with the carbonated water, use a medium glass, if its too large the gas will escape to fast;
    3. Drop the raisins in the water;
    4. Observe.
    What happens?
    The raisins will go up and down in the water for a while.
    The CO2 gas in water begins to free itself when we first open the bottle. This CO2 travels vertically through the glass until it comes into contact with the air, at this poit the gas is released into the atmosphere.

    When the bubbles of carbon dioxide meet the raisins those are immediately trapped in the grape rough skin imperfections, which will do the raisin “move up” to the top. When they arrive at the top CO2 bubbles are released in the air and the raisin falls down o meet another set of CO2 bubbles and go up again, and the cycle repeats itself. This will happen until there is not enough CO2 in the water to elevate the raisins.

    Make this demonstration a true experiment:
    • Use vinegar and baking soda. This mix will produce CO2. Do the raisins dance? Use plain vinegar with no additives
    • Use other carbonated beverages.
    • What drink is most effective?
    • Try to use drinks with sugar and with no sugar. Do you notice any difference in the dance?
    • Repeat the experiment using plain water and effervescent Alka-Seltzer® tablets.
    Remember, record all your observations so you can quickly draw conclusions. Use a timer to tell time.

    Et voilá!
    Raisins dancing!

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