Instant facts- Just add water 19

The oceans occupy nearly 71% of our planet's surface
in  http://savethesea.org

Instant facts- Just add water 18

January is the first month of the year, it was named after the god Janus (Latin word for door). Janus has two faces which allowed him to look both backwards into the old year and forwards into the new one at the same time.
in http://projectbritain.com

Gummy Bear Osmosis Demonstration

We already saw Osmosis here "Osmosis demonstration using eggs".

For those who do not remember:

Osmosis is the movement of solvent molecules through a membrane from a region of  lower solute  concentration, to a region of higher concentration.
In other words, and considering the solvent is water, osmosis is the movement of water molecules from "in" or "out" the cell, aiming to match the concentration on both sides of the membrane.

Today we are going to use gummy bears to see this "in" and "out" movement.

What we need:

• water
• flask with lid
• gummy bears

How to:

1. Wash the flask;
2. Fill it 1/2 with water;
3. Take a gummy bear, measure it;
4. If you have a nice scale try to weigh it;
5. Place the Gummy bear in the flask;
6. Close the flask
7. Wait 24h;
8. Remove the gummy bear, with careful

What happened?
The bear looks swollen

Why?
A gummy bear is essentially made of gelatin and sugar. We can read on the package

Glucose syrup, sugar, sugar sources;
Water, medium that allows gelatin to form;
Citric acid, helps to conservation;
Flavoring and coloring agents are responsible for the flavor and color;
Covering agents, allow the gelatin to maintain the form and texture;

So, jelly gums are most gelatin water and sugar, molded in a certain shape maintained by the covering agents.
As we seen here, water will travel from a less concentrated solute medium (in this case sugar) to a higher concentrated sugar solution medium. In other words the water will travel from exterior to the gelatin, why? Because the sugar contained in the gummy bear makes it a high concentration medium and the water gets "in" until the concentration is even in both mediums, the gummy bear swells, but it doesn't lose the shape due to the covering agents.

Before remove the gummy bear try:  
To observe the water against the light, to smell and to taste it.
Looks turbid, smells sweet and tastes like gummy bears.
Why?
Because although acting as a membrane, the gummy bear gelatin barrier is not a true membrane, and because the gummy bear is mostly made of water and sugar, some of this sugar ends up free in water, with some of the flavor coloring agents.
 
If you leave the bears a few days in water, the gummy bear stops to swell because reaches itsmaximum capacity point.
At this point we can observe a whitish substance, we couldn't found any information about this, but we believe this is the result of  exposuring the covering agents to water. The fact is when we tried to remove the gummy bear from water the gummy lost its form.

You can transform this demonstration in a experiment:

• Use different gelatin gums;
• Weigh and measure the gum before place it in water.
• After the 24 hours, what changes can you observe?
• Vary the time of the "bath". The gum reaches a point where it doesn't change the volume? When?
• Change the liquid "bath", using other substances such as honey, vinegar, sugar water ...
• ...

Remember:

• Always write down your observations.
• Don't change two elements (variables) at the same time.
• Do not stop to do a test because you think you know what will happen ... DO IT!

Et voilá!
Gummy bear science!

Enjoy!

Why days get shorter in the winter?- Answers to readers

Debbie wants to know why the days get shorter in the winter.

Before anything else it's important to be aware of some things:

1. Planet Earth its not a perfect sphere, its flattened on the poles;
2. There is an imaginary rotation axis that passes on these poles;
1. this axis, where the planet rotates has a inclination of about 23,45º,
2. this angle varied over the planet history;
3. Planet Earth moves in tow distinct ways: 
1. The translatory motion, around the Sun,
2. The rotation motion, around the imaginary axis.
4. Planet Earth describes a elliptic orbit around the Sun, this means the orbit its not perfectly round, that means the Earth is closer to the sun in certain times.
5. Seasons are the result of the axis inclination.

This image shows both motions:

The quick answer to the question "Why do we have winter and summer?" is the one described on the topic number 5., "seasons exist because the planet is closer/further from the Sun", WRONG, simply think a little and you will see this is not true. If this was true ALL the planet would be at same time in the summer or in the winter.

Let's say we are in North hemisphere, above the equator. If someone asks us about the seasons we will say March for spring, August for summer, autumn to Halloween, and of course winter for Christmas. However we don't think "why?” we don’t even think that is not true for everyone. In Brazil for example Christmas is summer, and autumn is March. While North hemisphere fills the beach, South hemisphere prepares for the winter.

Reasons for this are caused by the 23º inclination of the imaginary earth axis.
To understand this we must to be able to place ourselves outside the planet, in front of the Sun, observing the Earth "walking" around the star. Like the image shows the Earth turns around himself (rotation) and at same time moves around the Sun. Due to the 23,45º inclination of the Earth the planet orientation changes relative to the Sun along the year. This makes the length of the days to change along the year.

Now, imagine yourself in North hemisphere, looking to the draw is easy to understand that when the North Hemisphere moves away from the Sun, South Hemisphere approaches it (as if the planet is leaning back), we also note that when the planet is farthest from the Sun coincides with Winter in the North and summer in the South. Using the same logic we can say the inverse is also true.

Place yourself again in the planet, anywhere. Look at the Sun; what is the arc the Sun travels? During a whole year the path the star travels in the sky varies:
In the winter the path is shorter, and closer to horizon, and therefore takes less time to travel the distance;
In the summer the path is bigger, and far from the horizon, and therefore takes more time to travel the distance.

So, Debbie, the result of this is that in the winter the days are shorter and in the summer the days are longer, this variation is progressive like almost everything in Nature, therefore in autumn the days start to get shorter and in spring longest.

Note: the high and low temperatures that characterize the summer and the winter, are the result of this inclination, the "higher" the sun goes, the greater the angle of incidence of light is on the planet and because of that the amount of heat is greater. This conclusion leads us to other issues such as day length and extreme temperatures at the poles

Equinoxes- day is exactly equal to the night. In the North Hemisphere the Spring Equinox occurs in March, and the autumn Equinox in September.


20 or 21 March and 22 or 23 September


Solstices- when occurs in summer means that the length of daylight is the longest of the year. Similarly, when it occurs in winter, means that the length of the night is the longest of the year.


20 or 21 and June 21 or 22 December

Et Voilá!

Enjoy!

References:
http://www.newton.dep.anl.gov/askasci/env99/env221.htm 

Instant facts- Just add water 17

The number of possible ways of playing just the first four moves on each side in a game of chess is 318,979,564,000.
in Azimov, Isaac, 1991, "Isaac Asimov's Book of Facts"

Start the year with brain gym

Let's start 2012 with a brain teaser:
Don't use paper or a pencil, just your brain, be fast as keep adding the numbers, keep the calculator away from you

• Take the 1000 number,
• Add 40,
• Add another 1000,
• Add 30,
• Add again 1000,
• Add 20,
• Add 1000,
• And add 10.

Whats the total?


5000?


You should try again, the number is 4100!!!




What hapened?
Your brain is confused by the sequence of decimal numbers, and automatically jumps to the  higher decimal (que acontece e que a sequência decimal confunde o nosso cérebro, que salta naturalmente para a mais alta decimal (hundreds rather than tens).

Et voilá!
Another brain mistery!


Enjoy!

Instant facts- Just add water 16

The Holy Bible is the biggest selling book of all time