How to make Electromagnet at Home with cheap materials in 15min?

Do you know how to make a simple electromagnet at home with cheap materials in less than 15min?
It's simple, cheap and not dangerous.

Watch the video below, and try to make one at home.

Let's make learning physics to be fun.

Question:
How can you make a stronger electromagnet? 👧💪
Share your answer at the comment below.