Invention Ideas for 1St Grade Project - Mamapedia™ My son did this in 1st grade last year and the invention did not actually have to work. He just had to make a design of it and describe what it would do. I would stick with you daughter's idea and do the best you can. His idea was a cake machine that you just push the buttons to decide the type of cake you want and it makes a cake. Invention Ideas for Kids | LoveToKnow From easy inventions for kids using materials around the house to unique ideas that may require some outside materials, kids' invention ideas are limited only by their imagination. Help them learn how to look at the world with an eye for creativity, critical thinking, and problem-solving.