Respuestas para la especialidad JA de Burbujas

Burbujas

Nivel de destreza

2

Año

2015

Version

27.11.2024

Autoridad de aprobación

División Norteamericana

1

Definir los siguientes términos:

1a

Burbuja de jabón

1b

Hidrofílico

1c

Hidrofóbico

1d

Tensión superficial

1e

Energía mínima

1f

Superficie mínima

2

¿Cómo los siguientes factores climáticos afectan la vida de una burbuja y cómo?

2a

Humedad

2b

Temperatura

2c

Viento

2d

Precipitación

3

Hacer un modelo o dibujo de una molécula de jabón. Mostrar por qué la molécula es hidrófilo o hidrófobo.

Soap molecule

Soap molecules forming a bubble

A soap molecule has a hydrophobic end and a hydrophilic end. In other words, it is both hydrophilic and hydrophobic, and because of this, it corrals water, separating it from the air as shown here.

4

Hacer una lista de las normas de seguridad acerca de soplar burbujas.

• Soap solution will sting your eyes- avoid getting it in your eyes.
• Soap Solution is very Slippery- areas might still be slippery long after you are gone, so clean up any spills
• Never make bubbles near moving traffic.
• Soap solution can damage grass- dilute with water when finished.
• Don’t drink the bubble solution

5

Tensión superficial

5a

Explicar qué causa la tensión superficial.

5b

Hacer un experimento para determinar si el agua jabonosa tiene tensión superficial alta o baja.

Procedure

6

Sopladores

6a

Explicar qué tipos de materiales sirven mejor para el diámetro de sopladores grandes para burbujas.

6b

Construir un soplador para hacer burbujas grandes.

Bamboo garden poles work well and are inexpensive--basically two sticks with a loop of yarn or cotton cording strung between them.

7

Componentes

7a

¿Qué calidad de agua sirve mejor para las burbujas? ¿Cuáles impurezas afectan negativamente a la calidad de la burbuja?

It is best to use distilled water when making a bubble solution.

7b

¿Cuáles jabones son mejores para una solución de burbujas?

Dawn dish washing soap seems to work best but any dish soap will do.

7c

¿Cuál es el propósito de la glicerina o el jarabe de maíz en una solución?

Glycerin or corn syrup gives a bubble extra strength.

7d

Aprender una fórmula para una solución para burbujas y hacer una mezcla de esa solución.

Water Use good quality water that does not contain high levels of iron or minerals.

Soap When it comes to soap, Dawn dish soap seems to work the best for homemade bubble solution.

Glycerin This is the secret ingredient that gives a bubble its extra strength.

Formula # 1

• 2/3 cup (150 ml) Dawn dishwashing soap
• 1 gallon (4 liters) water
• 2 to 3 tablespoons (30-45 ml) of glycerin (available at the pharmacy or chemical supply house.)

Formula #2

• 1 cup (250ml) dish soap
• 14 cups 3.4 liters) water
• 1/4 cup (60ml) glycerin

7e

Evaluar su solución para burbujas y hacer una receta mejor, si es necesario.

8

Experimentos

8a

Mostrar lo que pasa cuando una burbuja se encuentra con otra burbuja. ¿Cómo esto ilustra la energía mínima y la superficie mínima?

When one bubble meets with another, the resulting union is always one of total sharing and compromise (Human beings could learn a lot from bubbles.) Since bubbles always try to minimize surface area two bubbles will merge to share a common wall. If the bubbles are the same size, this wall will be flat. If the bubbles are different sized, the smaller bubble, which always has a higher internal pressure, will bulge into the larger bubble

8b

¿Qué causa los colores en una burbuja? Demostrar interferencia constructiva y destructiva.

Similar to the way we perceive the colors in a rainbow or an oil slick, we see the colors in a bubble through the reflection of interfered light waves off the inner and outer surfaces of the bubble wall.

White light is made up of all colors, all wavelengths. If one of these colors is subtracted from white light (by interference, for example) we see the complementary color.

Interference All waves including light, have a curious property. If two waves combine, the waves meet each other crest to crest, adding up and reinforcing the effect of each other or they can meet crest to trough canceling each other out so that they have no effect.

Constructive interference is when two waves are in phase. The waves come together and make a bigger wave.

Destructive interference is when two waves are out of phase and they cancel each other out.

If we were to look at a highly magnified portion of a soap bubble membrane, we would notice that light reflects off both the front (outside) and rear (inside) surfaces of the bubble. But the ray of light that reflects off the inside surface travels a longer distance than the ray which reflects from the outside surface.

When the rays recombine they get “out of phase” with each other and interfere. Given a certain thickness of the bubble wall, a certain wavelength will be canceled and its complementary color will be seen.

8c

¿Qué forma tienen las burbujas y por qué? Hacer un experimento para ilustrar la respuesta.

Soap bubbles will assume the shape of least surface area possible containing a given volume. No matter what shape a bubble has initially, it will try to become a sphere. The sphere is the shape that minimizes the surface area of the structure, which makes it the shape that requires minimum energy to achieve.

Experiment

Bend pipe cleaners into several different shapes. Make as many different shapes as you can. You might want to make some square, some circles, some squares, some triangles, some heart-shaped or some even the shapes of letters. Make sure each one has a handle.

Carefully pour the bubble solution in a pie pan. Take each shaped pipe cleaner and dip it into the solution. Now start your bubble blowing.

What shapes are the Bubbles?

Record your Data.

References