Materials you will need: paper, markers, lemon juice, baking soda, grape juice, milk, Q-tips, and a flame-less heat source like a hair dryer or a lamp without a lampshade.
Optional items: ingredients for baking cookies, bread, or any other baked good
We would normally begin with a video of a read aloud that's connected to our subject, but this one can be a little tricky! Here's a great short video clip that summarizes all you need to know about physical and chemical changes.
Once you feel confident that you can determine the difference and physical and chemical changes, it's time to take on your STEM challenge! Ask yourself, how can I use household items to try and create secret messages that can only be revealed with heat? Give your messages one additional level of security by creating an alphabetic code that uses patterns to write your messages. Brainstorm some ideas and do some materials testing. Which type of chemical works the best? Create your secret code and give it to a family member to decipher. Evaluate: Could I try another material or combination of liquids to get better results? Can you improve your messages?
If you're stuck on how to create your code, check out this video and try out the Pigpen Cipher!