_Module 6 Second Class Activity - Science and Scientific Hypotheses

DeFever, Camden Module 06, Activity 02 GEOG 104: Principles of Physical Geography Science and Scientific Hypothesis Exploring the Scientific Method The scientific method is a process that scientists use to better understand the world around them. It includes making observations and asking a question, forming a hypothesis, designing an experiment, collecting and analyzing data, and drawing a conclusion. This is sometimes also referred to as scientific inquiry. A hypothesis is a possible explanation for an observation. A good scientist will design a controlled experiment to test their hypothesis. In a controlled experiment, only one variable is tested at a time. It is called the manipulated or independent variable. The experimental group will test the independent variable. The control group will be left alone, so you have something to compare your results to. The variable that determines the data is the responding, or dependent variable. It responds to the manipulated variable. All other variables in the experiment should remain the same, because if you change more than one variable, you will not know which variable explained your results. Once something has been tested many different times by many different scientists, it can become a scientific theory. It is different from a scientific law, which describes what will happen every time under a particular set of conditions. Part 1. Read through the following scenarios. Identify the control group, the experimental group, the independent variable, and the dependent variable. Scenario Independent Variable Dependent Variable Experimental Group Control Group A company wants to test a new dog food that is supposed to help overweight dogs lose weight. 50 dogs are chosen to get the new food, and 50 more continue their normal diets. After one month, the dogs are checked to see if they lost any weight. What type of food the dog eats The dog's weight The dogs that eat the new dog food The dog eats a regular diet A new sunscreen has been developed that is supposed to be more effective at preventing sunburn. 30 participants spray one arm with the new formula, and spray the other arm with the leading formula. After 4 hours in the sun, their skin is evaluated for any redness. The new sunscreen Skin redness Arm with the new formula Arm with the leading formula A student wants to study the effect of sunlight on plant growth. In his experiment, 12 plants receive normal amounts of sunlight, but half of them are kept under bright sun lamps all night long. After 6 weeks, the plants’ heights are measured. The amount of light the plants get Height of plants The plants that get extra light The plants get normal light

Part 2. Scientific Method In Action – The Strange Case of BeriBeri In 1887 a strange nerve disease attacked the people in the Dutch East Indies. The disease was beriberi. Symptoms of the disease include weakness and loss of appetite, victims often died of heart failure. Scientists thought the disease might be caused by bacteria. They injected chickens with bacteria from the blood of patients with beriberi. The injected chickens became sick. However, so did a group of chickens that were not injected with bacteria. One of the scientists, Dr. Eijkman, designed a new experiment based on his own observations. Before the experiment, all the chickens had eaten whole-grain rice, but during the experiment, the chickens were fed polished rice. Dr. Eijkman researched this exciting case and found that polished rice lacked thiamine, a vitamin necessary for good health. State the question or problem that Dr. Eijkman investigated. - The problem is nerve disease attacked the people in the Dutch East Indies What was the original hypothesis? - The original hypothesis was that bacteria caused the disease. What were the manipulated (independent) and responding (dependent) variables? - Injected chickens with bacteria - the chickens injected got sick, and so did the chickens not injected. Write a statement that summarizes the results of the experiment. - Dr. Eijkman discovered that the chickens were fed rice different from their normal diet, and because of that, the chickens lacked thiamine, an essential vitamin they need to be healthy. This made it clear a lack of thiamine causes the disease. How would Dr. Eijkman test his new hypothesis? - The disease is caused by a diet lacking in thiamine.

What are the independent and dependent variables in each of the experiments? - #1 Independent - water stored at different temperatures - Dependent - water evaporated - #2 Independent - water placed in front of a fan - Dependent - water evaporated - #3 Independent - water under different lights - Dependent - water evaporated What information should be added to the diagram to give the reader a better understanding of how these experiments were conducted? - How much water they started with, the time of the experiment What variables should have been CONTROLLED in the experiments? - Amount of water, a beaker with no changed temperature, fan, or ordinary light. How much confidence would you have in the conclusion of experiment 3 if you found out that temperature was not a controlled variable? Explain your reasoning. - I still have the same confidence in the conclusion of experiment 3 because the temperature is not the independent variable.