Trace necking
Okay, so imagine you have a really long and skinny balloon. When you blow air into the balloon, it gets bigger and bigger. But, if you blow too much air into the balloon, it can't stretch anymore and it starts to get really skinny in one spot, like a balloon sausage!
The skinny part of the balloon is called the "necking" part, and it can happen on other things too, like when we stretch and pull on rubber bands really hard. Sometimes in science experiments, scientists use a machine to stretch out materials and see if they can handle lots of stretching without necking.
So, "trace necking" just means that a material is starting to get a little bit skinny in one spot, but it's not fully breaking yet. It's kind of like a warning sign to tell you to stop stretching too hard or the material might break completely!
The skinny part of the balloon is called the "necking" part, and it can happen on other things too, like when we stretch and pull on rubber bands really hard. Sometimes in science experiments, scientists use a machine to stretch out materials and see if they can handle lots of stretching without necking.
So, "trace necking" just means that a material is starting to get a little bit skinny in one spot, but it's not fully breaking yet. It's kind of like a warning sign to tell you to stop stretching too hard or the material might break completely!