Scientific Method Worksheet(1)

Laboratory Assignment 1 Introduction to the Scientific Method – 10 points SKILLS YOU WILL PRACTICE IN THIS LABORATORY EXERCISE: FORMING A HYPOTHESES (MAKING PREDICTIONS) Suggesting ideas about how something will happen COLLECTION & ORGANIZING DATA. Recording factual information· Organizing information to facilitate analysis of your data SUMMARIZING Selecting only those facts which are key or pertinent GENERALIZING Draw a conclusion about a group based on information derived from a sample INTERPRETING Making statements supported by the data Recognizing the limitation of a sample size Incorporating other people’s viewpoints CONTENT FOCUS What is science? What do scientists do all day? These are not easy questions for most you to answer. The widespread idea of a nerd in a white lab coat does not apply to most scientists. So, what are scientists really like? They all have the three Cs" in common. Just as you are curious, scientists are CURIOUS about the world around them. They ask questions about everything and science is a method for answering those questions. Scientist do not accept things without COLLECTING information. All the facts relating to a problem or a question must be carefully explored and checked for accuracy. Scientists are COMFORTABLE with new concepts. If a better explanation can be found, scientists are not afraid to give up old ideas for new ones. To make the three Cs happen, scientist have developed a series of steps in investigation called the SCIENTIFIC METHOD. Through trial and error, the scientific method has proven to be an efficient and effective way to attack a problem. You have probably used some version of the scientific method many times in your life without being aware of the steps you were following.

ACTIVITY 1 -FORMING HYPOTHESIS: DARING TO BE WRONG Preparation A problem can come to your attention in several ways. Someone may assign you a problem, the problem may thrust itself upon you, or you may discover the problem by simply being curious about something you have seen. Let us begin with a simple situation that you might face in any day. THE PROBLEM You drive to school and park in your usual spot. As you walk across campus after your morning biology class, you discover that you cannot find your car keys. You have a problem! An easy way to attack the problem is to make an educated guess about the possible solution to the problem. It is an "educated" guess because you use all the background information that is available when making your guess. In scientific terms, an educated guess is called a hypothesis. 1. On the following table, you will find some hypotheses that might shed some light on this problem. 2.· Complete the table by adding some hypotheses of your own. TABLE 1.1 KEY LOSS: POSSIBLE HYPOTHOSIS 1. I did not bring my keys with me today. 2. The keys are in my book bag. 3. I left the keys in the car. 4. I left my keys in the class. 5. I dropped my keys in the hallways of the school. 3. A hypothesis will not help you solve your problem unless you can test it. Look over the hypotheses you recorded in the table. Is there a way to test each of these hypotheses? a. How many hypotheses did you cross out? On what did you base this decision?

An experiment is designed to isolate the factor you are interested in testing. All other conditions must be held constant. In this way, you are sure that your observed results were caused by the only factor that was varied (fertilizer being the variable ). Since you are investigating the effect of fertilizer, you will want to hold all other factors constant to avoid confusion. That way you can be sure that any differences in height are due the presence of fertilizer and not some other factor. You decide to measure the growth of your plants once a week for one month. You will keep detailed records of your observation. It is helpful to plan experiments with different groups of plants. There are two reasons to use groups: 1. If unexpected factors effect one or two experimental subjects, it will not ruin the experiment. 2. Natural genetic variability will cause some plants to grow taller than others. You can separate this effect from that of fertilizer by measuring height in a group of plants for each treatment. You can then use an average for the group, rather than the measurement from a single plant. You decide that five plants will receive identical measured amounts of fertilizer each week. These are the experimental plants. Five plants will receive no fertilizer. These are control plants. The do not receive the experimental treatment. You will use the control group for comparison with the experimental group to help you interpret your results, and show that any observed differences in height between the two groups are due to the only difference between them; the fertilizer. QUESTIONS 1. Why is it necessary to divide the plants into two groups (a control group and experimental group)? For the control group, you know what the outcome of the plant will be, but for an experimental group, you are testing it, and you don’t know. That is why you make a control group; to see or measure the difference between a normal or average outcome to the outcome of the experimental group. 2. Why is important to keep conditions the same in the control and experimental group, except for the application of fertilizer? Because that is what you are testing or exploring in this experiment. Everything else should stay the same between all groups for the application of the fertilizer to be studied. 3. Why is it better to do the plant/fertilizer experiment with five plants in each group instead of just one or two? Use your own words. It is better because if any accidents happen with any of them there are more test subjects. Also, having more test subjects lessens marginal error. ACTIVITY 4: THE DATA

Preparation The month is up. You are ready to draw a conclusion from your collected data. You will be thinking about what your results mean and whether your hypothesis is supported. The information you collected during your experiment is present in Tables 1.3 & 1.4 TABLE 1.3 HEIGHT GAIN (cm) OVER FOUR WEEKS - CONTROL PLANTS Plant Number Initial Height Week 1 Week2 Week3 Week 4 Total Height Gain Average Height Gain 1 10 1.6 2 3 2.5 9.1 2.3 2 9.6 1.5 2.3 2.6 2 8.4 2.1 3 10.2 2.3 1.2 1.6 2 7.1 2.5 4 9.7 4 2.6 4.0 2.3 12.9 3.2 5 10.4 2.3 2.3 2.7 2 10 2.5 TABLE 1.4 HEIGHT GAIN (cm) OVER FOUR WEEKS - EXPERIMENTAL PLANT Plant Number Initial Height Week 1 Week2 Week3 Week 4 Total Height Gain Average Height Gain 1 9.6 4.2 5 3 4.7 16.9 4.2 2 10.3 5.3 5.5 3.6 4.2 18.6 4.7 3 10.1 3.4 4 4.4 4 15.8 4 4 9.5 4.2 5.2 3.9 3.6 16.9 4.2 5 9.7 5.8 6.1 6.5 5 23.4 5.9 QUESTIONS 1. Were there differences in growth between the control and experimental plants? If so, which group grew taller?' How do you know? The experimental group. I know by adding the initial height to the total height gained. For the control group, the highest total height was 22.6 cm, and for the experimental group the tallest plant was 33.1 cm. 2. Do the results support the ·original hypothesis? Explain your answer. The results support the original hypothesis. The hypothesis was that if fertilizer is added to plants, then the plants will grow taller. The experimental group was given fertilizer, while the control group did not receive any fertilizer. The experimental group grew taller than the control group, which proves the hypothesis.