Oral sur la radioactivité en anglais

Euro anglais

Oral « Understanding Radioactivity»

Hello everyone ! Today, we’re going to explain something that sounds very scientific and a litle dangerous… But don’t worry, we’re here to make it simple and clear

I- What is radioactivity ?

First, what does the word mean ? « Radioactivity » means that something is emitting radiation, invisible energy, by itself.

So, radioactivity is when an unstable atomic nucleus decides to release energy to become more stable.

Think of it like a roly poly toy. When it spins nicely, it’s stable. But if it wobbles too much, it wants to correct itself, that’s what the nucleus is doing. It releases energy to fix its balance.

Now, there are different types of radioactive emissions. Let’s break them down :

- If the nucleus has too many neutrons, it emits a beta particle. That’s basically a fast moving electron.

- If it has too much protons, it emits a positron, that’s a positive electron !

- If it has too much energy, it releases a gamma ray, which is very strong, but doesn’t change the particles.

- If it has too much mass, it releases alpha particle, which is made of two protons and two neutrons.

So depending on what’s wrong inside the nucleus, it chooses a way to fix itself. Pretty smart for an atom, right ?

II- Why does this matter ?

Radoactivity is everywhere around us, in space, in the Earth, and even in our bodies. Some elements, like uranium, are naturally radioactive. Others become radioactive after being used in  hospitals.

Radioactivity is used in many fields :

- In medicine, to treat cancer or to diagnose problems inside the body.

- In archaeology, to date fossils using cabon-14

- And in nuclear energy, to produce electricity

III- How do we measure radioactivity ?

Radioactivity is measured by how many atoms break down every second. We call that  disintegration.

There are two main units :

The Curie (symbol : Ci) is named after Marie and Pierre Curie, who discovered radium. One curie = 37 billion disintegrations per second. That’s huge !

The other unit is the becquere (symbole: Bq), named after Henri Becquerel, who discovered radioactivity. One becquerel = 1 desintegration per second.

So if someone says a rock has 10 000 becquerels, it means that 10 000 atoms are breaking down every second.

IV- What is radioactivity half-life ?

Now let’s talk about something called half-life. It’s a way to understand how fast radioactive atoms disappear.

The half-life is the time it takes for half the atoms in a material to break down. For exemple if you have 100 radioactive atoms, after one half-life, only 50 are still radioactive. After another half-life, only 25 remain.

Here are some exemples :

- Uranium-238 has a half-life of 4.5 billion years. That means it will take that long for just half of it to decay !

- Lodine-131, used in hospitals, has a half-life of only 8 days !

This is super important in science, it helps us know how long something stays radioactive and how dangerous or useful it might be.

...