Does an Orange Float or Sink?

Does an orange float or sink when placed in water? Seems like a fairly straight forward question, but is it? Give this fun density science experiment for kids a try and answer the question while learning a unique characteristic of oranges.

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What you'll need:

An orange

A deep bowl or container

Water

Instructions:

Fill the bowl with water.

Put the orange in the water and watch what happens.

Peel the rind from the orange and try the experiment again, what happens this time

What's happening?

The first time you put the orange in the bowl of water it probably floated on the surface, after you removed the rind however, it probably sunk to the bottom, why?

The rind of an orange is full of tiny air pockets which help give it a lower density than water, making it float to the surface. Removing the rind (and all the air pockets) from the orange increases its density higher than that of water, making it sink.

Density is the mass of an object relative to its volume. Objects with a lot of matter in a certain volume have a high density, while objects with a small amount of matter in the same volume have a low density.

Experimenting with density

Rubrica de evaluación de blogs

 En cuanto al formato:

• Tipo y color de fuente
• Organización de información: Ejemplo cuadros

En cuanto a las actvidades propuestas

• Responsabilidad de hacer las tareas.
• Realizar lo que se pide en las mismas.

Task 4

Marcar  fecha de realizado / autor

Marca  fechas en el texto

Marcar  nombres en el texto

Footprints of the Atom

The Cambridge physicist C. T. R. Wilson was studying the formation of fogs in 1898 when he started on a train of ideas and discoveries which led ultimately to the perfection of the Wilson Cloud Chamber as a marvellous aid to nuclear physics. This first fog-making apparatus was, however, very simple just two glass jars connected by a pipe with a tap in it. One jar contained moist (saturated) air and the other was pumped empty of air. When the tap was opened the air expanded quickly into the empty jar. When gases expand very quickly they cool. You may have noticed that the air rushing out of a bicycle tyre when it is suddenly let down is quite cold. As a result of such cooling, clouds form in the moist air, since only a smaller amount of water vapour can be held by the air at the lower temperature.

Fogs cannot form unless the cooling is very marked. This is because small drops tend to evaporate again more easily than the large drops. It is therefore very difficult for any drops to begin to form at all unless they form immediately into large drops, as they would if the cooling were pronounced. The dust particles in ordinary air act as a very convenient beginning for the drops, because they are already of sufficient size for the drops formed on them to avoid re-evaporation. This explains why fogs and mists are much more common and more persistent near large manufacturing towns, where there is a lot of smoke and dust, rather than in the clear air of the countryside.

Wilson soon discovered that even if he used very clean air he still occasionally got clouds with only a moderate amount of cooling when there was some radio-active substance or a source of the then recently discovered X-rays near his cloud chamber. He soon showed that this was because the air in his chamber was being 'ionized' by their radio-activity or by the X-rays.

Let us see what happens when air is ionized. The atoms of the various gases that make up air are all built of a heavy positive nucleus surrounded by very light negative electrons. The amount of positive charge on the nucleus is exactly balanced by the number of negative electrons surrounding it, so that the atom as a whole is electrically neutral. Although it takes quite a hard knock by a particle from one of the powerful 'atom-smashing' machines to break off a bit of the nucleus, the negative electrons are held to the atom only by the electrostatic attraction of opposite charges between negative electron and positive nucleus. It is therefore much easier to remove an electron from the atom, either by strong electro-magnetic radiation (X-rays) or by collision with another atomic particle like those shot by radio-active substances.

Before impact the atom was neutral, but after it has lost a negative electron it becomes a positively charged 'ion'. The electron it has lost is a negative ion; it is free to move until it joins another positive ion to form a neutral atom. When an atom is split in this way into two ions, positive and negative, we say it is ionized.

If ions of this type are present in moist air their effect is twofold. First, they attract many more normal atoms to themselves, with the result that a cluster of atoms is formed. Secondly, the charge on the ion reduces the tendency of small drops to evaporate. All this means that the charged ions in moist cooled air act as suitable nuclei, like dust and smoke, on which fog and clouds can form.

To make this clear we will follow up what happens when an alpha-particle passes through a cloud chamber immediately after expansion has taken place, and when the moist air has been cooled so that it is ready to form clouds. An alpha-particle is a fragment shot out of the nucleus of a radio-active atom. It is about four times as heavy as a hydrogen atom. It has a double positive charge, and it will travel a few inches in normal air before it is brought to a stop by repeated collisions with the atoms in the air. While it is travelling very fast through the air of a cloud chamber, its positive charge attracts many of the outer negative electrons of the atoms in the air, which may be drawn i out of their original atoms, leaving them ionized.

The passage of one alpha-particle thus leaves a trail of ionized atoms behind it all along its track, each of which is capable of acting as a centre about which a tiny drop of water can form. If the alpha-particle is shot into the moist air of a cloud chamber just after a cooling expansion has taken place, so that the air is supersaturated, a trail of little water drops appears in its wake, looking just like the cloud trails left by a high-flying aircraft.

The first time that an atomic nucleus was split artificially was in 1919 when Lord Rutherford turned a nitrogen atom into an oxygen atom by bombardment with alpha-particles. This nucleus-splitting reaction has been studied by Professor Blackett with the aid of a cloud chamber. He obtained an actual photo graph of the famous event. In this photograph a beam of alpha-particles appears as white trails crossing the chamber. One of them stops half-way as it hits a nitrogen atom in the air and the lighter trail of a proton (a positively charged hydrogen atom), knocked out of the nitrogen nucleus, moves off to the left, while the resulting oxygen nucleus gives a thick short trail to the right. We have come as close as we can to actually seeing the invisible atom.

(From an article by R. R. Campbell in Adventures in Science edited by B. C. Brookes.)

Task 3

Texto “What is addiction?...

Afirmaciones que sé

1. La adicción es la dependencia a sustancias yo actividades.
2. Genera problemas a nivel físico, químico, emocional.
3. Necesita un tratamiento para la rehabilitación.

Preguntas genuinas.

1. ¿Que sienta una persona adicta?
2. ¿Tipos de tratamientos?
3. ¿Qué postura toma el Estado frente a los tratamientos de adicciones?

Síntesis

Vídeo representativo de Adicción

https://www.youtube.com/watch?v=WCYAK5DgwCI

3) Convalidating information

Text A

Text B

Conectivismo: Teoría del aprendizaje, para la era digital. Principios del conectivismo: En cuanto al Aprendizaje: _ Proceso de conectar nodos especializados o fuentes de información        _Puede residir en un dispositivo no humano.      _El aprendizaje se produce a través de las conexiones dentro de las redes. El modelo utiliza el concepto de una red con nodos y conexiones para definir el aprendizaje.       _ La capacidad de saber más, es más importante que lo que se conoce en la actualidad y   establecer distinciones entre la información importante y la no  importancia es vital.

El conectivismo es una teoría del aprendizaje para la era digital. Principios del conectivismo En cuanto al Aprendizaje: _El aprendizaje es un proceso de conectar nodos o fuentes de información.  _Puede residir en dispositivos no humanos _Objetivo: el aumentar de la capacidad de "hacer algo". _ Capacidad de ver las conexiones entre los campos, ideas y conceptos es una habilidad básica. _ Saber dónde encontrar información es más importante que saber la información.

What is Connectivismo

Connectivism is a learning theory promoted by Stephen Downes and George Siemens. Called a learning theory for a digital age, it seeks to explain complex learning in a rapidly changing social digital world. In our technological and networked world, educators should consider the work of thinkers like Siemens and Downes. In the theory, learning occurs through connections within networks. The model uses the concept of a network with nodes and connections to define learning. Learners recognize and interpret patterns and are influenced by the diversity of networks, strength of ties and their context. Transfer occurs by connecting to and adding nodes and growing personal networks. (Connectivism Wikiversity) According to George Siemens, "Connectivism is the integration of principles explored by chaos, network, and complexity and self-organization theories. Learning is a process that occurs within nebulous environments of shifting core elements – not entirely under the control of the individual. Learning (defined as actionable knowledge) can reside outside of ourselves (within an organization or a database), is focused on connecting specialized information sets, and the connections that enable us to learn more are more important than our current state of knowing. Connectivism is driven by the understanding that decisions are based on rapidly altering foundations. New information is continually being acquired. The ability to draw distinctions between important and unimportant information is vital. The ability to recognize when new information alters the landscape based on decisions made yesterday is also critical."

Siemen's Principles of connectivism:

•       Learning and knowledge rests in diversity of opinions.

•       Learning is a process of connecting specialized nodes or information sources.

•       Learning may reside in non-human appliances.

•       Capacity to know more is more critical than what is currently known

•       Nurturing and maintaining connections is needed to facilitate continual learning.

•       Ability to see connections between fields, ideas, and concepts is a core skill.

•       Currency (accurate, up-to-date knowledge) is the intent of all connectivist learning activities.

•       Decision-making is itself a learning process. Choosing what to learn and the meaning of incoming information is seen through the lens of a shifting reality. While there is a right answer now, it may be wrong tomorrow due to alterations in the information climate affecting the decision.

http://education-2020.wikispaces.com/Connectivism   

[30/07/14]

  Task 1

Lo que se	Lo que quiero saber	Lo que he leído
Definición     Sustancias que generan la adicción     Comercializables legalmente	¿Cómo afectan el Organismo?    Mecanismos de control.     ¿Por qué la persona llega a ser adicta?

What Is Addiction? What Causes Addiction?

People with an addiction do not have control over what they are doing, taking or using. Their addiction may reach a point at which it is harmful. Addictions do not only include physical things we consume, such as drugs or alcohol, but may include virtually anything, such abstract things as gambling to seemingly harmless products, such as chocolate - in other words, addiction may refer to a substance dependence (e.g. drug addiction) or behavioral addiction (e.g. gambling addiction).

This article focuses mainly on addiction to physical substances.

In the past addiction used to refer just to psychoactive substances that cross the blood-brain barrier, temporarily altering the chemical balance of the brain; this would include alcohol, tobacco and some drugs. A considerable number of psychologists, other health care professionals and lay people now insist that psychological dependency, as may be the case with gambling, sex, internet, work, exercise, etc. should also be counted as addictions, because they can also lead to feelings of guilt, shame, hopelessness, despair, failure, rejection, anxiety and/or humiliation.

When a person is addicted to something they cannot control how they use it, and become dependent on it to cope with daily life.

A habit may eventually develop into an addiction

Many of us can use substances or become engaged in activities without any significant problems. Some people, however, may experience damaging psychological and/or physical effects when their habit becomes an addiction.

What is the difference between a habit and an addiction?

§  Addiction - there is a psychological/physical component; the person is unable to control the aspects of the addiction without help because of the mental or physical conditions involved.

§  Habit - it is done by choice. The person with the habit can choose to stop, and will subsequently stop successfully if they want to. The psychological/physical component is not an issue as it is with an addiction.

Put simply - with a habit you are in control of your choices, with an addiction you are not in control of your choices.

Addiction to substances or activities can sometimes lead to serious problems at home, work, school and socially.

The causes of addiction vary considerably, and are not often fully understood. They are generally caused by a combination of physical, mental, circumstantial and emotional factors.

Addiction, often referred to as dependency often leads to tolerance - the addicted person needs larger and more regular amounts of whatever they are addicted to in order to receive the same effect. Often, the initial reward is no longer felt, and the addiction continues because withdrawal is so unpleasant.

According to Medilexicon's Medical Dictionary:

Addiction is Habitual psychological or physiologic dependence on a substance or practice that is beyond voluntary control. Withdrawal has many meanings, one of which is A psychological and/or physical syndrome caused by the abrupt cessation of the use of a drug in an habituated person.

According to the current Diagnostic and Statistical Manual of Mental Disorders (DSM-IV), published by the American Psychiatric Association:

Substance dependence is When an individual persists in use of alcohol or other drugs despite problems related to use of the substance, substance dependence may be diagnosed. Compulsive and repetitive use may result in tolerance to the effect of the drug and withdrawal symptoms when use is reduced or stopped. This, along with Substance Abuse are considered Substance Use Disorders..

Addiction may include prescription medications

Most people think of illegal drugs when they hear the word “addiction”. However, prescription drug addiction is becoming a serious public health problem in the USA and many other nations. Prescription medication abuse was described as “an epidemic” by researchers from the University of Nebraska Medical Center College of Medicine in a study they reported on in November 2012.

The scientists explained that doctors today treat pain differently than they used to years ago. This change has led to an increase in prescription drug abuse.

In the USA in the 1990s - the decade of pain treatment - not only was there a change in medication, but also policy. Pain became the fifth vital sign doctors looked out for, along with respiratory rate, blood pressure, body temperature and pulse rate. Doctors’ offices today commonly have signs in their waiting rooms asking patients to rate their experience of physical pain from 1 to 10.

Pagina

http://www.medicalnewstoday.com/info/addiction/

Fecha [ 28/7/14]