Can you mix enzymes to make a yummy treat? Learn more about yeasts and microbes by creating your own living, breathing, sourdough starter. Gather a jar, flour, water, a fork, and a breathable lid for this bubbly challenge with Librarian Davey.

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STEM Challenge Yo’Self is created by the San Francisco Public Library from the Youth Librarian STEM team. Stay STEM-tastic by reading, learning and experimenting at home. Gather materials for a new challenge posted weekly at 2pm on Mondays followed by a Live STEM Zoom Lab with SFPL on Tuesdays at 2pm.