Exploring Radioactivity with Students with Visual Impairments

By Hari Bhimaraju on May 14, 2015

In my last post I talked about my teaching tool, which helps students learn about the periodic table of elements with drawings of the atom, audio to explain, and LEDS and beeps to show the valence electrons.  However, no study of the periodic table is complete without learning about RADIOACTIVITY. That is why I decided that it would be a great addition to my project.  Here is a study of why it is important to learn about radioactivity, followed by an extension to my tool above showing the Geiger Counter Simulation, and a new tool and a tactile model that teaches about the different types of radiation.
 

Why It Is So Important To Learn About Radioactivity

  1. No study of the Periodic Table is complete without understanding radioactivity, because there are 38 naturally occurring elements, which are radioactive (not including naturally occurring isotopes like C14 and other synthetically radioactive elements).
  2. It is something that happens so much in nature and has such huge effects, that we should know about it to understand the world around us.
  3. Radioactivity is often used in life-changing medical treatments, like X-Rays and cancer treatments. It is very important that we have this medical technology to save peoples’ lives.
  4. Radioactivity is also used in everyday life. For example, did you know that the strawberries you regularly buy at the grocery store might have been exposed to gamma rays to increase their shelf life (a process called irradiation)? Strawberries that are treated this way can last for up to 30 days without spoiling!
  5. Did you know that the age of fossils is determined using “radioactive dating”? For example, every living organism has a fixed ratio of C14:C12 in him or her. And a clock starts ticking at death, reducing the ratio of C14, but keeping C12 constant. This is used to determine the age of fossils!
  6. Radioactive isotopes are widely used in scientific research. For example, to see which kind of soils are helping plants grow the best, the tracks of ocean currents, the absorption of a newly made fertilizer by a plant and so on.
  7. There are also many, many more uses to amazing radiation! Here is a list: commercial applications, electricity, nuclear power plants, reactor safety, hydrogen generation, industrial applications, food irradiation, medical uses, space etc. It is just phenomenal how many things radiation helps us with!
It is very important to know about the radioactivity that helps us in so many ways!
 

Geiger Counter Simulation:

dial indicating level of radioactivity

First I extended my periodic table tool, so that for the radioactive elements, it says and prints on the screen that they are radioactive. 
 
Further, I researched and found that there are 5 levels of radioactivity: very low (1), low (2), medium (3), high (4), very high (5). So besides telling it is a radioactive element, it also tells which level of radioactivity the element belongs to.
 
The Geiger counter is an instrument used to measure the level of radioactivity. It is a meter that shows how much radiation there is and sometimes it also comes with beeps.
 
I simulated this, so that there is a dial and it moves to the indicated level of radioactivity, and also beeps as many times as the level is. So for a very high radioactive element, it would beep 5 times. Braille stickers are added to the dial, so the visually impaired can touch and feel, which level the needle, is pointing to. They can also hear and count the beeps, and hear the tool tell about it.
 

The Different Types of Radioactivity

Besides the above, I made a new teaching tool and a physical model that teaches and explains about the different types of radiation for someone who is eager to learn more!
 
alpha radiation particle diagram
Alpha Radiation:  
An Alpha particle is made up of two protons and two neutrons. Once released, the particle will not travel very far in air. This is because, in just a few centimeters, it accumulates electrons, turning into a Helium atom within seconds. In fact, most of the Helium in the atmosphere comes from Alpha Radiation! Alpha particles are very massive, making it very hard for them to penetrate through any surface. External exposure to alpha radiation poses no danger--even human skin can stop them without getting damaged! However, ingesting or inhaling them, leads to almost certain death. As, due to their massive size, they cause disruptive damage to cells leading to the failure of major organs. This radiation takes place when an atom has too many protons and neutrons and it is in a hyperactive, unbalanced state. As a result of Alpha Radiation, the atomic number of an atom will go down by two and the mass number will decrease by four, lending more stability to the nucleus. To the right is a picture from my tool, explaining this radiation. It talks as it draws, to aid the visually impaired to understand.
 
beta (minus) radiation diagram
Beta (Minus) Radiation:
A Beta Minus particle consists of one electron. While the Beta Minus particle is MUCH smaller than an Alpha particle, it penetrates farther than an alpha particle, but not too much, as being just an electron, it gets attached to some other atom there by ionizing it. It can easily pass through skin (unlike the Alpha particle), but can be stopped by a thin sheet of aluminum. Normally, Beta Radiation takes place when an atom has too many neutrons in comparison to protons, resulting in a high-energy, unbalanced nucleus. The atomic number increases by one and the mass number stays the same. My tool draws as it voices showing this (see video).
 

 
Gamma Radiation:
gamma radiation diagram
Gamma Radiation is waves of energy. Gamma waves are given off when an atom is in a highly energized state and needs to let out some energy. It is the product of radioactive atoms. Its wave length is less than one-tenth of a nanometer, making it the most energetic wave of the electromagnetic wave spectrum. Emitting Gamma Radiation makes no difference to the radioactive atom other than making it more stable (by reducing excess energy), but it will ionize other atoms by ripping away their electrons (due to the excess energy). It penetrates the most! My tool shows this (see right):
 
 

Model of Alpha, Beta, and Gamma Radiation:

model of alpha beta and gamma particles
 
 
In this model, the giant Alpha particle is being stopped by someone’s hand (skin). The much smaller Beta particles are being blocked by a thin sheet of Aluminum. Finally, the Gamma rays are piercing into a thick block of Lead, only being stopped halfway through the block. This model shows how strong each type of radiation is. This is a special tactile model built so the visually impaired can also feel the model and understand what it is showing.
 
 
 
Beta (Plus)/Positron Radiation:

beta (plus) positron diagram

The Beta Plus/Positron particle is made up of a positron (a positive electron). This radiation takes place when the atom has too many protons and is super energetic. A proton becomes a neutron, releasing a neutrino and a positron. This decreases the atomic number by one, but makes no difference to the mass number. This radiation, however, is very weak. This is because, as soon as it is released, the positron will immediately meet an electron and cancel itself out into nothingness (since positrons and electrons are opposites). That’s why this radiation doesn’t travel very far.
 
electron capture radiation
 
Electron Capture Radiation: 
In Electron Capture Radiation, a proton captures a first-orbit electron and becomes a neutron, releasing a neutrino. Then, an outer orbit electron fills the inner orbit hole, emitting X-Rays and (if the nucleus is still in a high-energy, excited state) Gamma Rays. This takes place when an atom has too many protons, but not enough neutrons (since you are losing a proton and gaining a neutron). It will decrease the atomic number by one and make no difference to the mass number. In addition, the Gamma Rays and X-Rays will ionize other atoms.
 
 

My Project’s Applications to the Visually Impaired

  1. Voice. Everything, and more, which is written is said out loud for the visually impaired to hear and understand. 
  2. Beeps. Beeps are used multiple times in my project. First, when LEDs are lighting up to show the valence electrons, beeps are produced so the blind people know when the lights are coming on. Second, in my simulation of a Geiger counter, special beeps are made for every category number so that the visually impaired know what category the element is in, and to make it easier to understand exactly how radioactive the element is.
  3. Dial with needle and braille: The dial with needle and braille stickers in the Geiger counter simulation help the visually impaired to get a good idea of how radioactivity the element is, as they can touch and feel it.
  4. LEDs. To show the valence electrons of the element, LEDs light up. If there is a visually impaired student who can see bright lights, they will still be able to tell which LEDs are lighting up, and will, therefore, understand the Lewis Dot Notation.
  5. Tactile model of the types of radiation: This is something the visually impaired can touch and feel to understand the different types of the most common types of radiation.

 

radioactivity collage

 

 

Hari in front of science fair projectHari winning her award

 

 

 

 

 

 

 

 

 

 

 

 

 

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