Reloj de sol

Los relojes de sol son herramientas que te dicen la hora simplemente con las sombra del sol, para diseñar un reloj de sol necesitas saber donde los vas a poner, necesitas conocer la longitud, la latitud y la orientación de la pared con respecto al norte. 

El reloj de sol más antiguo conocido fue hallado en Egipto y data de la época de Tutmosis III, unos 1.500 años antes de nuestra era. Se trataba de dos listones de piedra, uno que hacía de aguja y otro donde estaban marcadas las horas.

Después de este ejemplar, hemos de avanzar hasta el 750 a.C. para tener referencias de otro reloj de sol, éste en una cita bíblica donde se nos cuenta como Jahvé hizo retroceder diez grados la sombra del cuadrante.

 Por otra parte, se atribuye a un tal Beroso, babilonio, el diseño de un reloj de sol cóncavo, hacia el siglo IV a.C.

Algunos enlaces para construir un reloj de sol:

Construir un reloj de sol de pared

Reloj de sol de cuadrante ecuatorial

Aquí podemos ver el proceso completo en el que unos alumnos construyen un reloj de sol:

El astrolabio

El astrolabio es un aparato antiguo, utilizado durante mucho tiempo para medir la latitud y actuar como auxiliar en la navegación. Los historiadores creen que los primeros astrolabios fueron ideados por los antiguos griegos, entre los que encuentran los astrónomos Apolonio (262 a.C. - 190 a.C.) e Hiparco (190 a.C. - 120 a.C.), quienes desarrollaron la teoría detrás del dispositivo.
Si bien existe mucho debate acerca de quién construyó el primer astrolabio, el consenso es que Hiparco tiene ese honor, al utilizarlo como una forma mucho más precisa de medir la latitud que un gnomon. El astrolabio es un instrumento que permite a los observadores medir la posición de los cuerpos celestes en relación con el horizonte, lo que permite la ubicación precisa de las estrellas. La utilidad del instrumento no termina allí, ya que también puede ser utilizado para medir la latitud, dar la hora local y estimar la altura de los objetos. Los astrolabios fueron utilizados por los topógrafos para medir la distancia por medio de la triangulación. El astrolabio común consiste en un disco con un brazo giratorio completo con vistas, pero los cuadrantes, sextantes e inclinómetros utilizan el mismo principio.

Aquí podemos ver un uso práctico del astrolabio:

Una comparación entre un iPhone y un Astrolabio:

En esta página web tenemos información y plantillas para la construcción y uso de un astrolabio casero:

Asociación astronómica de Valencia

La mentira de las bombillas de bajo consumo

Las bombillas de incandescencia se retiraron para minimizar la emisión de gases de efecto invernadero. En su lugar se emplean las bombillas de bajo consumo, que son más eficaces, pero, en su interior guardan un un veneno mortal y muy peligroso, el mercurio. ¿Debemos seguir utilizando estas bombillas? ¿Cuál será la mejor opción? ¿Cuáles son las ventajas y los inconvenientes?

¿qué quieres hacer con tu vida?

Una crítica acerca de la pasividad ante el cambio climático, el consumismo, el consumo energético...

Representaciones gráficas - #Refugiados

La distribución de refugiados propuesta por la CEE es la siguiente:

Alemania 31443, Francia 24031, España 14931, Polonia 9287, Países Bajos 7214, Rumanía 4646, Bélgica 4564, Suecia 4469, Austria 3640, Portugal 3074, República Checa 2978, Finlandia 2398, Bulgaria 1600, Eslovaquia 1502, Croacia 1064, Lituania 780, Eslovenia 631, Letonia 526, Luxemburgo 440, Estonia 373, Chipre 274 y Malta 133.

Representar los datos en una tabla.

Podemos calcular:
-¿Cuál es la cantidad media de refugiados en cada país?

-Busca el número de habitantes de cada país y calcula la relación entre refugiados acogidos y número de habitantes total.

-Representa gráficamente el total de refugiados.

Tipos de gráficos:
a) Líneas
b) Columnas
c) Circular

El mundo a través de una lente

http://cdn.shopify.com/s/files/1/0901/0816/products/10882230_841227679257264_8058514408035086066_n.jpg?v=1435006577

Jabón casero

Cold-Process All-Natural Handmade Soap posted bySTEPHANIENOVEMBER 12,201124 COMMENTS tagsHANDMADE HOLIDAY GIFTS, NATURAL SKINCARE SERIES, SOAP, WEEKEND PROJECTSEDIT 104K+ UPDATE: Welcome! This post has been so popular that I thought I might add some of the amazing soap recipes that I have made over the years or that book authors have so graciously shared here. Did you know that there is a whole natural skincare series of posts here on Garden Therapy? From soaps and lotions to bath bombs and tub teas you will find plenty of ideas for gifts as well as all the bath products you will to use at home! Garden Therapy Natural Skincare Series - recipes inspired by the garden Now back to the tutorial on: Lemongrass Ginger Coffee Kitchen Soap, Rosemary Spearmint Energizing Shower Soap, and an Orange Vanilla Cinnamon Holiday Soap recipes Nourishing all-natural soap makes a wonderful gift for yourself and others. This post describes the step-by-step instructions on how to make cold-process soap, plus has three amazing recipes to try (scroll down to the bottom of this post for the recipes): Lemongrass Ginger Coffee Kitchen Soap Rosemary Spearmint Energizing Shower Soap Orange Vanilla Cinnamon Soap All are made with natural vegetable ingredients, pure essential oils, natural colours, and herbs from the garden. You can feel good about taking care of those who use your handmade soap. gorgeous soap with all natural color and essential oils from How to Make All Natural Cold Process Soap Ingredients There are so many recipes you can use to make the base of soap. Here are a few options: You can start with a basic soap making recipe such as this basic olive oil soap from the Pink Grapefruit Soap Recipe: Mix temp 115°F Oils 170 grams shea butter 170 grams palm oil 113 grams coconut oil 113 grams olive oil Lye mixture 78 grams sodium hydroxide (NaOH) 215 grams distilled water Want something even easier? Well, you can use a pre-weighed soap making kit like this Natural Soap Making Kit or this Shea Butter Soap Making Kit. Perhaps there is another recipe you would like to try? There a a lot of great soap-making recipe books: The Natural Soap Chef The Best Homemade Natural Soaps: 40 Recipes for Moisturizing Olive Oil-Based Soaps Soap Maker’s Workshop: The Art and Craft of Natural Homemade Soap Soapmaking the Natural Way: 45 Melt-and-Pour Recipes Using Herbs, Flowers & Essential Oils Basic Soap Making: All the Skills and Tools You Need to Get Started (Kindle) Get the ingredients here: Purveyors of fine herbal products Soap Making: Cold Process Method 1. If you are not using a kit, the first and most crucial step in cold-process soap making is to weigh the raw ingredients (fats, lye, water) precisely. Prep everything that you will need and lay it out accessibly before you begin.how to make handmade soap ingredients 2. It’s best to wear protection when making soap as lye can burn your skin. Until the oils and lye have turned into soap (48-hours after making the recipe) it’s best to protect yourself. Always wear rubber gloves, safety goggles, and keep area free from kids and pets. 3. OILS: Gently (aka slowly) heat oils in a stainless steel pot on the stove. Alternatively, use a microwave and heat for 2 minutes on high, and then at shorter intervals until you reach the temperature listed in the recipe. 4. LYE: Using room-temperature distilled water, weigh the amount specified by formula into a heat-resistant glass bowl or large Pyrex measuring cup. While stirring, slowly add measured amount of lye. SLOWLY. Stir until dissolved. This mixture will get super hot and quickly so be mindful of that. Also, the fumes are terrible, so if you can stir from below the fumes (with lye on the counter and you crouching below as you stir) with windows open that would be best. Place glass containing in an ice water bath and cool to required temperature. Get accurate temperature readings with a candy thermometer in the middle of the solution. 5. When both oils and lye/water are at the required temperatures (as stated in your recipe), slowly pour lye/water into the oils while rapidly stirring in small circles. Always add lye/water to oil, not the other way around.Tracing soap from How to Make All Natural Cold Process Soap 6. Continue to rapidly stir the mixture until it thickens to the consistency of pudding (called tracing). The mixture is ready to be molded when a drizzle mark from the spatula remains for a few seconds on the top of the mixture. Speed up the tracing process by using a hand blender to mix. Be careful not to over mix. 7. Add essential oils, natural colorants, and herbs or exfoliants at this stage (see recipes below). Work quickly as the mixture will quickly start to thicken. The ingredients you add should be good for your body so avoid perfumes, fragrance, and artificial colors. Your hand-made natural soap is best scented with pure essential oils and colored with natural dyes as outlined in the recipes. 8. Pour mixture into 1L milk cartons and staple the tops shut. Wrap the cartons in a large towel and set somewhere warm for 48 hours like the top of the fridge. The cartons will feel warm and will get hot as the mixture neutralizes and turns into soap. Use a milk carton as a soap mold - from How to Make All Natural Cold Process Soap 9. To unmold your soap, peel off the milk cartons and cut each full 1 liter carton lengthwise into 3 equal sections for shower soap, and 4 equal sections for hand soap. Flip each section so that it appears to be a square from the top, and cut into 3 equal sections.Use milk cartons as soap molds and you from How to Make All Natural Cold Process Soap 10. Place each bar on a wire rack in a cool, dark place to cure for 3 weeks. 11. After 3 weeks, soap can be buffed with a cotton cloth and wrapped for gifts.Cold Process handmade soap RECIPE with all natural ingredients Soap Recipes Lemongrass, Ginger, and Coffee Kitchen Soap Lemongrass and Ginger Cold Process handmade soap RECIPE with all natural ingredients Add 1 tablespoon dry, finely ground coffee at trace Scent with 15ml lemongrass and 5ml ginger essential oils Colour with turmeric Rosemary and Spearmint Energizing Shower SoapRosemary and Spearmint Energizing Cold Process handmade soap RECIPE with all natural ingredients Scent with 10ml rosemary and 10ml spearmint essential oils Colour with sage powder Gently stir in spirulina powder to make a darker green swirl Orange Vanilla Cinnamon SoapOrange Vanilla Cinnamon Cold Process handmade soap RECIPE with all natural ingredients Add 1 tablespoon dry, finely ground coffee at trace Scent with 7ml orange, 7ml cinnamon, and 7ml vanilla essential oils Colour with cinnamon Gently stir in cocoa powder to make a chocolate color swirl Step by step instructions on how to make beatiful artisan soap at home http://gardentherapy.ca/handmadesoap/