Preschoolers have some of the most imaginative and expansive minds. What better way to get those amazing little minds turning than a “hands on brains on” science experiment. This science experiment was not a “Watch and see what happens” experiment. Rather an experiment involving hypotheses and predictions. You may ask, “How might a preschooler be able to make predictions?” Yes, preschool minds are mostly engaged in the present, but when they are interested in a topic and have the ability to observe, feel, smell, explore, and investigate the subject their engagement turns from interest to fascination.
During the desert unit my class had a great interest in the cactus. We read the book Cactus Hotel during a morning circle and afterward cacti came up during conversation throughout the day as well as many questions about this interesting desert plant. We decided to complete an experiment of our own to see firsthand how this plant can survive in an extreme desert climate.
We discussed how cacti need water to survive, just like other plants. The class understood that the desert is dry, and rarely has rain. When it does rain cacti needs to somehow to collect and absorb as much water as possible. Cacti have a unique waxy coating that helps protect from absorption. Once discovering this characteristic, our experiment began.
We began by cutting sponges in the shape of cacti. We added toothpicks to resemble the protective spikes. We then filled two small glass jars with equal amounts of water using the new tablespoons added to our science center. We placed each “cactus” into a jar and watched them immediately soak up water. We then made predictions as to how much water would be gone in the morning. This question really got the class thinking with some prompting. What does a sponge do? How does a cactus receive water when it rains? Some of the predictions were: “I think it is going to soak up all the water.” “The water is going to get smaller.” “The cactus water is going to be gone and we are going to find out and talk about it tomorrow.”
The following day we observed the two cacti. They had both soaked up almost every drop of water. We decided they must have been very thirsty in the “dry desert”. We were excited to find out that our predictions were correct. We continued the experiment by putting wax paper around one of the cacti to observe how the waxy protective barrier that a real cactus has in the desert helps store the water during the long hot months without rain. We asked the class how the waxy protective coating would help the cacti. Some of their predictions were: “It won’t end up dead.” “So it won’t dry up.” “It will stay wet.” “So it can keep growing.”
We left the two cacti on a tray over night. One was wrapped in wax paper (the protective coating) and the other was left exposed to “the elements.” We made predictions as to which cactus would dry out faster and checked our predictions in the morning. We also asked the class what they through would happen to the cactus without the protective waxy coating. Some of their predictions were: “The one will die without wax paper.” “The one that is covered will
keep soaping the water and the other one will die.” “The cactus will keep drinking water.”
We are happy to report our findings from our experiment. The cactus with the waxy protective coating held its water throughout the night and even through the next few days. The cactus without any protective coating was all dried out after one night. The protective coating is one of the main reasons why the cactus can survive in the dry desert.
We were able to learn so much from this experiment. The class used great teamwork each day to share their thoughts with one another and put them all together to form one big idea. During this experiment we also were able to explore the properties of a sponge and wax paper. Each day the class was so excited to find out if their predictions were going to be correct. The exploration of the cactus was one they will never forget.