Our teacher Madia suggests:

How about continuing with some experiments? This time, we ‘re gonna try an explosive combination of materials and in the end we ‘ll see how we can keep a secret message hidden! Let lemons, vinegar and baking soda do their magic!
Have fun!!!

Keep creativity and fun alive with another science project! Madia has designed an online STEAM workshop (check vol.1 here) and prepared a video with a collection of various easy experiments with materials that we have at home.