I did a homeschooling science-experiment-in-a-bag swap that called for me to distribute 5 drops of food coloring. Instead of using emptied & dried single-use water bottles as the instructions laid out, I decided I’d try these DIY backpacker single-use packets because I had several straws from recent hospital stay food service trays on hand. I figured everyone in the swap had kitchen glasses that could be used for the experiment instead, and straw packets would be much less bulky for storing the experiments. I did put the straw packets inside snack bag sized ziplocs in case of failure, and because I had already bought a box of those for a different experiment in the swap (each family was assigned 2 experiments from a book the organizing hostess had purchased).
The food coloring is for a science experiment involving white flowers. You put one flower in red-dyed water, one flower in blue-dyed water (with a little cooking oil added to the water as well to prevent evaporation so you can see how much liquid they “drink”), plus one flower in both colors by splitting the stem up the middle part way. Might be a fun experiment if/when you have your Easter egg dye out, after dying eggs. The proportions are 1/2 cup (4oz) water, 5 drops food coloring, 2 tablespoons cooking oil. The experiment calls for white carnations, but I believe any white flower would work such as a Shasta Daisy if you happen to have them as part of your garden beds.