martes, 7 de marzo de 2017

Sundial Project

If you want to know what time it is, you probably watch at your wristwatch or mobile phone. But imagine that you live some centuries ago... Sundials are the oldests known instrument for telling the time. In fact, the earliest known sundial was made by Egyptians about 3.500 BC. As the Sun moves across the sky, the shadows objects cast move too. And people use this movement to know the time.
There are two parts in a sundial. One of them is called a gnomon; normally a stick that cast a shadow. The other one is a flat surface with marks, one for each hour of the day, where the shadow is projected. This is the dial plate. Those marks are usually numbered lines, the hour lines, that show the hours of the day. As the day passes, the gnomon' shadow moves around the dial; the shadow falls on a new line every hour.
Our Science Week is coming; and as every year, we are going to work about sundials. We are going to learn about these instruments, how they work, different types of sundials. And the most important... you are going to build your own sundial. Don't worry; it's very easy. Here you have some sundials made by students last year.

But, in my opinion, it is important to know about sundials in Granada too. How many sundials are there in Granada? Where are they? What kind of sundial is every one of them? Answer these questions as comments. Please, and if you can, take photos of those sundials. Send them to me and I will include your images in our blog.
And now, a very difficult question: where is the sundial of the picture below?

Construcción de relojes solares. Incluye la descripción de los principales tipos de relojes de sol así como plantillas de los cuadrantes solares para relojes orientados.
Algunos modelos de relojes solares.
Relojes solares otras semanas de la ciencia del IES Zaidín Vergeles.
La sombra del tiempo. Relojes solares del IES Zaidín Vergeles en el diario Granada Hoy.
Son muchas las páginas web dedicadas a la gnomónica y a la construcción de relojes solares. Algunas de las más representativas son:
Relojes de Sol de Mallorca.
Reloj andalusí. Web andaluza de relojes solares.
Relojes de Sol de la provincia de Málaga.
Asociación Amigos de los relojes de Sol.
North America Sundials Society.
Sundials on the Internet.

lunes, 13 de febrero de 2017

Life in a drop of water

A drop of untreated water is a very small world. Hundreds of small microorganisms like protozoans, bacteria and algae live there. We have colected different samples of water; in the laboratory we have deposited drops of water onto a glass slide, we have covered it with a cover slip and observed with a microscopy. There are lots of different small organisms living there. Here you have some pictures taken in our laboratory. We have observed protozoans like Paramecium or Vorticella, algae, even small pluricelular animals as rotifers, also known as wheel animals. We have found some parasite eggs too! 
What do you think about our experience? Try to draw one of these small organisms; I will publish the best drawings in our blog.

Parasite egg.
And here we have some of your drawings:

A Rotifer. Ainhoa Yolanda Monero Duperón, 1º ESO B.

A rotifer watched with a Foldscope. Ignacio Mengíbar, 1º ESO C

lunes, 9 de enero de 2017

Does acid rain affect leaves?

Finally, we have study the effect of acid rain on plant leaves. So, we have observed if there is any difference in leaves aspect in plants irrigated with acid solution. The results are in the following images. Can you see damaged leaves in the pictures? Can you describe differences between these two plants?

Leaves after acid rain treatment.
Leaves of plants irrigated with water,

The following pictures have been taken with a  magnifiying glass. So you can watch the difference in a better way.

Leaf treated with a solution of acetic acid 0,1%.
Leaf treated with water.

Acid rain and plants growth

We had six plates used as controls with germinated lentil seeds. Three of them have been irrigated with a solution of acetic acid 1%. The rest have been irrigated with water; these are now our control plates. The results are shown in these two pictures. You can see the difference in growth after some days of treatment.

Small lentil plants watered with acid rain.
Small lentil plants watered with water.

We had grown lentil seeds in pots. Half of them were watered with water and the rest with a simulated acid rain (acetic acid 1%). Nine days later we studied the growth of the plants. In this photo you can see both groups of plants.

Plants growth. Irrigated with water (left) and acetic acid solution 1% (right).
We want to study of acid rain affect the growth of plants; so, we had planted lentil seeds and we have measured the length of stems and roots in plants nine days later. The results are in the following tables. The first one shows the results in plants irrigated with acetic rain. The second one shows the results of the control set, irrigated with water.

Plants growth with acid rain

Plants growth irrigated with water.

What do you think about the influence of acid rain on the growth of plants? Are there differences between plants trated with water and with acid solution? How does acid rain affect plants growth? Please, write your answers as comments.

Acid rain and plants germination; final results.

These are the final results of our experiment about the effect of acid rain on the germination of lentil seeds. We have tested low concentrantions of acetic acid and only with acetic acid 0,1% we have obtained positive results. However the proportion of germinated seeds is lower than in seeds germinated only with water. In the next table you have the data.

Please, study the result of our experiments and write your conclusions.

miércoles, 21 de diciembre de 2016

Seeds do not germinate with high acetic acid concentrations

Some days later we have realised that seeds do not germinate with high concentrations of acetic acid. So we decided to prepared news solutions with 0,5% and 0,1% of acetic acid. Only some lentil plants have germinated in solutions with acetic acid 0,1%. You have the results in this table.

We have made more experiments. We have transferred seeds treated with high concentrations of acid to water. And these seeds are not able to germinate five days later. In conclusion, acid damages seeds permanently.

With our control plates we have made two sets with three plants. All al the plates had small lentil plants. One of these set has been irrigated with acetic acid 0,1%; the other one with pure water. We are going to study differences in the growing of lentils plants.

viernes, 16 de diciembre de 2016

Our results, 16th December 2016

Today we have observed that no seeds have germinated in acid media. Almost all the seeds grew only in water have grown. You can see the result in the table below.
We are going to study if the damage caused by acid is permanent. So we have removed the acid and put the seeds into water and we are going to study if they can germinate next week.
We have a lot of small plants. We have divided them in two groups. One will be irrigated with water. The other one will be watered with a solution of acetic acid 1%, simulating acid rain. Next week we will see if there is any effect on the leaves and growth of the plants.

jueves, 15 de diciembre de 2016

Seeds are germinating

Now we have our first results. Almost all the control seeds, those watered, with water have germinated. On the contrary, no seeds have germinated in acid media. We will have to wait to the next days. 

In the second experiment, seeds have germinated and we can see the small plants in the pots. When they grow, half of them will be treat with an acid solution remembering acid rain. 
So, we can have our first conclusions. Would you mind to write them as comments?

miércoles, 14 de diciembre de 2016

Our experiments with acid rain

You know that rain is an important part of the water cycle. Rain is also very important for life; all living beings need water to live, even people, and rain brings us the water we need. But rain can be dangerous in some parts of the world because of pollution of the air. This rain is what we know as acid rain.
Acid gases are produced when fossil fuels are burned. But nature can also produce this kind of gases in volcanoes. When they mix when the water in clouds it can cause rain to become acid. Lemon juice, vinegar are acids; and sometimes rain is as acid as lemon juice.
Acids can be harmful. If there is too much acid in soil, seeds will not germinate and plants will not grow. Leaves affected by acid rain cannot make photosynthesis.
So, we are going to study the effect of acid rain in plants in our laboratory. We are going to prepare two experiments. In the first one we are going to study the effect of acid rain on the germination of lentil seeds. We are going to prepare some Petri dishes with 16 seeds. We are going to add only water to five of them; we will add different solutions of acetic acid in water to the rest. We will study the germination of seeds in every plate for a time.
In the second one we are going to grow lentil plants until they have leaves. Half of the plants will be watered with fresh water; the rest will be irrigated with a solution of acetic acid. We will study differences between these two treatments. In our blog we will post pictures with our results. Please, contribute to our research with comments.
(Spanish version)



And our first results

Two days after the beginning of our experiment, we have our first results. Two seeds have germinated in control plates. No seed have germinated in plates with acid solutions. Here you have a picture of these plates.

miércoles, 23 de noviembre de 2016

The water cycle

You know that the water on our planet is in constant movement. For example, water goes from seas to clouds, and from clouds to the surface of our planet. This movement is what we know as the water cycle.
The water cycle is the process in which the Earth's water moves between the hydrosphere, the atmosphere, the geosphere and the biosphere.
This is possible thanks to the energy our planet receives from the Sun and the gravitational pull. Heat causes water to change the state; gravity moves water from higher points to lower ones, in the seas. Here you have a picture with the cycle water.

The water cycle (from USGS).

Here you have a link to an interactive diagram about the water cycle.
Here you can study the water cycle in Spanish.

And finally, an activity. Fill the gaps in this diagram with the processes of the water cycle. You can download the diagram from here.