What is deflection?

Deflection is when something bends or moves because it’s being pushed or pulled from one side.

Imagine you're holding a straw, like the ones you sip soda through. If you press on one end of the straw, instead of just squishing flat, it might bend in the middle. That bending is deflection. It's like when you push on a swing set from the side, instead of just moving forward and back, it might also sway from side to side.

Think of the straw as being made up of many tiny, stiff sticks inside. When you press on one end, those sticks don’t like being squished all at once. So they push against each other, kind of like when you try to squeeze a bunch of pencils together in your hand. That pushing and shoving makes the straw bend instead of just getting shorter.

This is exactly what happens with bridges or beams in buildings. When heavy trucks drive over a bridge, it doesn’t just collapse, it bends slightly under the weight. That bending is deflection too! It’s like giving the bridge a gentle push and watching it sway back and forth.