Start with one ball that fits through the tube. Put it in on one side and lift that side so the ball comes out the other way. Talk to your child about what you’re doing. “Let’s put the ball in here. Is it going to fit? Yes! What will happen if I lift the tube? Wow! It came out the other side!”
Look through the tube at the child on the other end. Let the child try it and comment on what is happening. Try making different faces for your child to copy or label.
Once the child has had an opportunity to explore the tube and ball, you can add other balls of different sizes. Some will fit, some won’t. Try reflective talking with your child by speaking about what your child is doing. “You put the ball in the tube!”
Have fun experimenting together and talk about what is happening to enrich the child’s understanding and vocabulary. Use words like “big, bigger, biggest, small, smaller, smallest, fits, doesn’t fit.” Ask the child what they think will happen (making predictions).
Source: Let’s Play: Activities for Families Set 1 - Engagement with Others, Materials and the World