She already made observation, and she has asked her question, which is why the plants grow at different rates. she would then form a hypothesis about her observation: "if I test to see why the two groups of Ivy grow at a different rate, then it will be because of the temperature" she would conduct an experiment using controls and one variable, the variable being temperature. recording data using an independent variable (what you test) and a dependent variable (what you measure). after recording her data and comparing the results, then she can draw her conclusion. I hope this has helped you.
