1. Martin Cooper's invention
was heavy and took a long time to charge.
became famous immediately.
was very expensive.
3. The first YouTube video and Instagram photo both involved
food.
family members.
animals.
4. Tim Berners-Lee and Jack Dorsey
both used mobile phones to develop a new product.
included messages about their new invention when they first
invented the same piece of technology at the same time.
2. Robert Cornelius
worked with Louis Daguerre to make the first camera.
took a picture of his family.
sat still for a long time for the first selfie.