Question
Hi I am the 7th grade student again. I was wondering also how much shampoo should I put in the water cause you are right it will probably die.

Answer
What I would do is have one plant that you water with just water, and five other plants that you mix shampoo in a cup of water (the first cup of water add 1 teaspoon of shampoo, the next 3 teaspoons, the next 5 teaspoons, the next 7 teaspoons, the next 9 teaspoons). Water the plants with these mixtures and watch the plants growth. This experiment will have 6 plants each being watered with a different mixture of water and shampoo (one with only water).