This is a new post in my Think Like a Scientist series. I must be very successful in “discovery” experiments, because my 7 year old cannot get enough of them. This time we explored an unknown liquid.
Setting Up an Experiment
I set up a liquid discovery experiment with three different types of “white substances” – cornstarch, soda and cream of tartar. I also added several test tubes, water to make solutions, and a brown “unknown liquid” – iodine solution. This time I was hoping not only to show Smarty some spectacular chemical reactions, but also teach her a thing or two about lab techniques.
Learning to Plan an Experiment
My daughter immediately wanted to dump some of the unknown liquid into one of the “white stuff” containers, but I stopped her and pointed out that this will immediately “contaminate” her substance. We talked about setting aside some part of the substance for experimenting or making a solution of “white stuff”. She chose to make a solution and then see if each of white substances dissolves in water and how they will interact with “brown stuff”.
Describe the Results
Eventually Smarty went wild in her testing and started dumping her unknown liquid into our containers. She discovered that starch turned very dark purple, while cream of tartar turned bright orange. She could guess already by that time that her unknown liquid was iodine solution, since it has a distinctive smell, and we use iodine solution for making a gargle for sore throats (a remedy that I myself experienced from my childhood back in the Soviet Union).
Think of What You Can Do with the Results
Smarty was very interested to try her mixtures as paints. She thought that her paintings were very “artsy”, and it was interesting to see differences in color from different mixtures.
More “Think Like a Scientist” Resources
- Separate Two Materials
- Predict, Observe, Explain
- Explore an Unknown Substance
- What Failed Experiments Can Teach You
Follow my Pinterest Science Board.
How do you teach your children simple lab techniques?
I am linking this post to my favorite kid blogger link ups and share days