Stephanie J. Sheehan
One of the main goals of the unit is to encourage students to think critically and think of themselves as scientists. Therefore, the children will need to use the Scientific Method to problem solve. First, the teacher will make a chart to creatively display the students' ideas and fill it in by asking the students to say and write words they associate with scientists. This will be followed by a shared reading lesson using a passage about the scientific method. A great selection to use in second or third grade can be found in the book, Bill Nye The Science Guy's Big Blast of Science, by Bill Nye. The teacher will use the overhead projector (or photocopies) to make the reading selection accessible to all students. He or she will read aloud as the students read along silently or aloud in unison. The reading will be interrupted by discussion of key words, such as reason, controlled, etc. and followed by questioning to verify that the passage was understood. This passage will be reread and discussed over the span of two or more days, so that students will have a chance to read, understand and discuss it. Then, the students will write a paragraph to answer a question to show their understanding, such as "Would you want to use the scientific method to solve a problem in your own life?" The students would then answer, giving information about a specific problem or question in their own life that would or would not be solved this way. After the students have learned about what it means to be a scientist, they should revisit their scientist idea chart to see what they have learned and revise any misconceptions they may have had.
The class will then be ready to learn about liquids and solids. First, the teacher will help the students make a KWL chart, which will show what they think they Know about solids, what they Want to know, and leave room for what they will have Learned at the end of the unit. The students may suggest ideas such as "solids are hard" and "solids don't move by themselves." The teacher will demonstrate the difference between a liquid and a solid by putting an apple in a clear container and then moving it to several other clear containers with different shapes. He or she will repeat this with apple juice, pouring the juice from one container to the next. The students will observe that the juice takes the shape of each container while the apple stays the same shape.
12
The students will notice that the juice flows and the apple does not. This demonstration will bring the students closer to the working definitions they will use during their initial explorations of solids and liquids. Of course, they will ultimately challenge these definitions and examine liquids and solids more closely through additional lessons and experiments later in this unit.
Based on the previous demonstration, the teacher will then display at least twenty different materials and ask the students to identify which are solids and which are liquids. The materials to display (which can be found in the STC science kit, as directed by Carolina Biological Supply Company.) are shampoo, water, oil, corn syrup, a wooden cube, a clear plastic cube, plastic condiment lids, rubber balls, a small metal ball, two types of plastic spoons, a small wooden golf tee, a small gem stone, a crayon, a ping pong ball, a metal nut and a silver metal washer, a brass washer, a small pipe cleaner, a small cork, a bobby pin, a square magnet, a button, a paper clip, a sponge, and a clear plastic cylinder. The teacher will assign science buddies and put away the liquids for later in the unit. He or she will then provide each pair of student buddies a large container with 20 different solids to examine.
