| Procedures/Activities: |
1.)Motivation:
Place 4 different colored flowers in pop cans full of water. In a fifth can pour a food coloring into the water (I suggest red) and place a white carnation into the can. Over several minutes, the carnation will change color and appear either light pink or red. Place the arrangement of different colored carnations at the front of the room. Say to the class, "These are a type of flower called carnations. Perhaps you have seen them before. As you can see, they come in a variety of colors. However, one of these carnations was a different color when it was picked. Write down the colors that you see and try and guess which one of the carnations has a new color. When you have guessed, explain how you think the flower came to be the color it currently is." Allow students to inspect the flowers but do not allow them to look in the cans.
2.)Once the students have had time to observe the flowers and write their assumptions, ask students for their guesses and make tally marks on the board next to the colors. After several have guessed, ask other students for their explanation of the phenomenon.
Tell the class the correct answer (the fifth can), but do not explain how the flower came to have the color it does; only state that the flower used to be white. Explain that they will discover the answer later on their own.
On the board write, The Scientific Method. Check for prior understanding or knowledge of this concept.
Explain the separate aspects of the scientific method: hypothesis, experiment, collection of data, evaluation of data, and re-testing. Ask how this is used in science and why it's important to use. Try and direct the discussion towards understanding that scientists must first ask questions, state what they believe the answer is, try an idea out (experiment) to see if their answer works, collect the information from their experiment, decide if their answer was correct.
3.)Hand out the Scientific Method Data Sheet (attached). Inform the students that they are going to practice the scientific method. Also inform them that the question they are going to be trying to solve is, "How can the color of the flower be changed and how does this happen?" Read the directions aloud as they follow along and have them write the question down in the space provided. Explain that they are going to be working in their groups and that each person needs to come up with an answer to the question (hypothesis); they may use the answer they had written earlier or come up with a new one. Also explain that they need to follow the directions carefully, work together, and decide on three of the hypotheses to test. All three hypotheses can be tested at the same time.
Pass out the white carnations, food coloring, glasses, and place the water pitchers on the sink or your desk. Have plenty of paper towels handy.
Check for understanding and answer questions. Set the timer for 15 min and go!
After the timer has gone off, check to see if any groups need a bit of additional time to complete the task. Also, if you notice that all the groups have finished before the timer goes off, go ahead and move on to the next step.
4.)Have each group report what hypotheses they used, how they tested the hypotheses, and what the results of their experiment were.
Assuming that someone figured out how to get the carnation to change color, have that group direct the rest of the class in performing the experiment. If students did not figure this out, ask for other options from the rest of the class until someone mentions the correct procedure or you can give them a clue.
Once everyone has had the opportunity to view the change, show the class the food coloring in the can of the colored carnation and ask, "What do you think will happen if I placed clear water back in the can?" Take answers, dump out the food coloring, and put clear water in the can. Eventually, the carnation will return to being white as the students have hopefully predicted.
Ask, "Why do you think the carnation changed color?" Begin a discussion on how the stem has veins that move water and nutrients throughout the plant's body, like the veins in the human body. Use the posters or transparencies at this time. Pass out the plants with the roots still intact so that they can see and feel the roots. Continue to discuss how the plant uses sunlight to manufacture energy and food, how water and carbon dioxide are taken in and oxygen expelled, and how soil types affect the type of plants that either flourish or perish. Give examples of plants that live in the arid, tropical, mild, cold, or aquatic settings.
5.)Have students visit this website during centers or stations as a follow up activity. ( The Great Plant Escape) Help Detective LePlant and his partners Bud and Sprout unlock the amazing mysteries of plant life!
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