When notice about the science fair came home in February, I knew Brennan would want to participate. He loves doing experiments. Initially, he wanted to create a volcano, but the science fair pushed you to create a question and hypothesis to test. So, we did a little online research and decided to test the following question: "Does water temperature affect how quickly celery absorbs water?" Here were out supplies:
We ended up with two snow days the week before the science fair, which gave us the perfect opportunity to stay home and work on the experiment. We set out 5 jars with food coloring and water of differing temperatures: boiling hot, hot tap, room temperature, cold tap, ice cold. Brennan's hypothesis was that the boiling hot would absorb the fastest. he set his celery in and we started to watch the results.
Brennan was very excited to get to work, though afterwards, when I printed these pictures to put on his display board, he said, "Mom, I'm wearing pajamas in the pictures!" Well, that is something you can get away with in first grade!
Brennan tracked the celery absorption after 10 minutes, 30 minutes, 1 hour, and two hours. The boiling hot turned out to be the slowest - I think the boiling water may have cooked the celery, slowing down it's ability to absorb. By the time two hours passed, the food coloring had made its way to the top of all the celery stalks (the room temperature and hot tap water made it to the top in 1 hour.) The boiling hot did eventually reach the top of the stalk, but it took 4 hours.

I helped Brennan make his display board. We printed the headers, but he hand wrote most of it. His conclusion was that room temperature water and hot tap water were the best for celery absorption. Unfortunately, the day of the science fair, Brennan came home from school with a stomach virus. We had already dropped his display board off for viewing, but he missed the fair itself. Thankfully, his teacher allowed him to present his work to his class when he returned to school. He was so excited and it is already talking about next year's fair.