I think you bring up a great question, but I don't think that science always needs to be an experiment with all kinds of materials. I think science can even just be wonderings, questions, or thinking about solutions. It can be about anything. I think that NGSS is interesting in the way that it is based in inquiry, wondering, and phenomenon. It ties in well with your question. I have some suggestions that might be helpful.
Students could draw their questions or wonderings and bring it to school with them. Maybe you could give students a journal with a pen so that they have that at least. They could even glue a collection of whatever they wonder about. I always used to have kids that collect little seed/beans that fall of the tree, different colored leaves, sticks. Honestly, just things that interest them and spark engagement.