What fate is awaiting for the Universe?

In these days we have been discussing about the universe in our class. We have learnt that the universe began with a hot explosion known as Big Bang. This theory states that all the matter and energy in the universe were concentrated into a single small point. Then, after that explosion, the universe was bigger and bigger and still it is expanding today. But will the universe expand for ever? What fate is awaiting for our universe? I am going to give you some clues. Big Crunch, Big Rip, Big Freeze... I wonder why the name of all the theories about the universe begin with Big?

In my opinion this is a very important question and I am very interested in your opinions. You have read some of them in our class but I want to know all of them. Let me know as comments.

What has happened with the horoscope?

In ancient times, people believed that the Earth was the center of the Universe and the Sun rotated around our planet. Today we know that the Sun is in the center of the Solar System and every planet orbits our star. They also observed the sky and connected the stars with lines drawing pictures known as constellations. They were convinced that those constellations were important symbols telling stories about their gods and myths and were very useful in order to know about people personality  and predict their future too.

The ecliptic. By Tauʻolunga - Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=935439

As a result of the motion of the Earth around the Sun, our star appears to pass in front of different constellations. This apparent path of the Sun on the celestial sphere marks the ecliptic; the constellations through which the sun passes define the zodiac. Consequently, all the zodiac constellations lie along the ecliptic.
Babilonians, about 3.000 years ago, had a 12 month calendar, so they decided to divide the zodiac into twelve equal parts. For them, there were twelve zodiac constellations and this is the origin of the twelve signs listed in the horoscope that everybody knows. For example, if you were born under the sign of Leo, it means that the Sun was in this constellation in that moment and, of course, every year at your birthday.
But... is it true? Recently some newspapers said that NASA have changed the astrological signs for first time in 2000 years; consequently, lot of people now have a different zodiac sign. In my opinion, this is not a great problem for people who don't believe in horoscope, but what happens with the other people? Has their luck changed? 
I think that this is a very interesting matter that we can investigate. An to begin with, just some easy questions:
What do you know about zodiac? What is your zodiac sign? Can the stars really predict the future or describe what are people like based on their birth date? Please, write your answers as a comment.
(Spanish version)

Andalucía mejor con ciencia: a short video

There are several schools in Andalucia working in order to improve the environment and to do science with people. Here you have a short video, produced by Fundación Descubre. We can see our project. Soon we will expose our results in a congress.

How can we improve our environment?

Our results are clearly conclusive. Both, seeds germination and plants development are affected by products we usually use at home for cleaning or personal care. The inhibit germination of lentil seeds and growth of small plants. In conclusion, we have an environmental problem. And we have to solve it. And this is not only your responsability. 

I invite you to talk to your parents, your brothers and sisters, about the results of our experiments. It is important for them to know what we know, that home products can affect living beings and environment. An of course, we need to change our habits.

How can we reduce the impact of using these products? Please, write your decisions as comments.

How did our plants grow?

We have finished the next experiment. We have planted lentil seeds and we have waited until they have germinated. When small plants appeared, we treated them with disolutions of our home pollutants. 

Ten days lated, we had new results. Our lentil plants had grown but we noticed differences between treatments in growth. Here you have some pictures:

When plants were grown we pulled up the plants and we measured stalk lenght, root lenght and we weighed plants. We have compared results with different treatments. And here you have our results. What are your conclusions? Do our pollutants affects plants and environment? Please write our conclusions.

Final results of the germination experiment

And these are our final results for the experiment of germination. What can you conclude about the effect of home pollutants on the germination of lentil seeds? Write your conclusion as comments!

New experiments

Now, we are going to grow lentils plants to study the effect of home pollutants on growth and development of lentils. This morning we have put 10 lentil seeds into containers with potting soil. We have recycled used yogurt cups for this experiment. We have watered them. When seeds germinate, we will treat them with the pollutants and we will study the growth of plants. We will have untreated plants, watered only with water, as control experiments. 

New results

We have repeated some experiments. Seed didn't germinate in water with detergent at concentrations of 5% and 10% (weight/volumen concentration). So, we have studied lentils germination at lower concentrations (1% and 0,5%). We have tested another washing up product and we have repeated the experiment with hydrogen peroxide. In the previous experiment, seeds germinate with high concentrations of acetone; this wasn't the expected results as this product is toxic. So we have tested the effect of nail polish remover on germination as this product contains acetone. No seeds have germinate with concentrations of 10% and 5% (w/v); we are going to test lower concentrations this week. Finally, fabric softener doesn't seem to affect lentils germination as concentrations as high as 20% doesn't inhibit germination.

Please, study this data and make your own conclusions. Write them as comments.

Our first results

After a week, we have our first results. In our control experiments, all the seeds irrigated with water have germinated. But we have observed differences between treatments. Here you have a table with our results. What are your conclusions? Is there any experiment with unexpected results? Will we have to repeat any experiments?

Control plate

Washing up liquid, 5%.

Grease remover 5% and 10%.

A new research project for our younger students: Home pollutants

Surely, your family has lot of chemical products for domestic use at home. Some of them are detergent or fabric softener; we use them for washing our clothes. Bleach, grease remover or antilime cleaner are used for cleaning our houses. All of them contain toxic chemicals we leave to the environment. And it is the same with other products we use with our own body like the alcohol or the hydrogen peroxide we use to disinfect wounds or the nail polish remover we use for cleaning our painted fingernails. Do they affect living beings?

This is the main goal of the project we are beginning. We are going to study if this products are toxic for the environment, especially for plants. We want to know if they affect aspects of plants biology as germination, growth and development of plants.

We begin our experiments studying the effect of these products on the germination of seeds. We are going to use lentil seeds (Lens culinaris). We have prepared seed germination chambers with Petri dishes; we have placed paper towel inside the plates and we have added 20 ml of the different solutions of chemical products. We have put 16 seeds per germination chamber.

We are going to carry out control experiments. In some plates we will add only water. We want to know the viability of seeds irrigated only with water. Later on, we will compare the number of germinated seeds in plates with water and chemical products. We consider that seeds have germinated when they show a little root at least one millimeter long. We will study seeds germination for a week.

(Spanish version)