Scientific Inquiry. Deborah Turner

Transcription

1 Scientific Inquiry Deborah Turner

2 CHAPTER 1 Scientific Inquiry The Scientific inquiry is a process of steps that scientist use in order to explain and idea. Steps normally are in order for the following process. These steps are: purpose, hypothesis, designing an experiment, collecting data, and conclusion.

3 SECTION 1 Steps of Scientific Inquiry Now let s look at each step separately to try to understand how a scientist goes about explaining an idea. First, purpose: this is the question or idea you want to prove or explain. Next is the hypothesis, this is your question on what you think may happen in the experiment. Then comes designing an experiment, this is when you actually do an experiment related to the question proposed. Next, is the data collected? You will have to measure, graph, or even calculate time when you complete your experiment. Finally the conclusion, this is when you look at your data and come to a conclusion to see if your hypothesis is correct or incorrect. Your data must back up your hypothesis either way. By completing this experiment another Scientist can pick up your information and redo your experiment from your data or even add or delete according to the question the Scientist has regarding what you have done. This is how Scientists continue to work on ideas that they have. This is the process that Scientists use in everyday life to help in medical, engineering and many other areas of Science. 2

4 Now let s look at a scenario regarding a Scientific Idea and how to break down a Scientific Idea in each step. Ladybug has lost her cell phone and cannot find it. She was in her science class today and learned how scientist follows steps in order to solve problems. Let s see how to finds her phone. 1. Purpose (question): Where is my cell phone? 2. I think I left it in my room.(hypothesis: your guess) 3. Experiment: I will trace my steps from last night to try to figure out where my cell phone is. 4. Data: 1st in the living room with phone talking to Kelsie. 2nd bathroom washing hair 3rd. watching TV in family room with mom and dad. 4th getting up homework in bedroom and talking to Lucas. 5th getting bath left phone on table beside books 6th ready for bed, talking to Zack in bed. Turned night light off put phone down. Hum but where? 5. Analyzing data: have traced my steps. Looks like the last place I had my phone was in bed. Now looking on bed table, hum no phone. Looking in drawer on bed table. Hurrah my phone. 6. Conclusion: My hypothesis is sort of correct. It was in my room but to be specific, it was in my bed table drawer. 7. Notes regarding experiment. Now I understand how Scientist resolves problems but I also see that they need to be specific in their hypothesis. I m glad I paid attention in class today. This scientific method really works. Now that you have seen how each step is done it s your turn. Read the next scenario and complete each step. Does the size of a fish tank determine how large gold fish will grow in the tank? Purpose: Hypothesis: Experiment: Data: Analysis: Conclusion: Review your results with your class. Now that we have worked through the Scientific Method, we need to add variables. Variables are any factor, trait, or condition that can exist in differing amounts or types. Independent variables are things that are changed by a scientist. Dependent variables is observed by the change made by the independent variable. Controlled variables are quantities that scientists want to remain constant, and must be observed carefully as the dependent variable. Experiments need to be repeated 3 to 5 times for accuracy. 3

5 Scenario with variables: Mitchell notices that his Grammy s shower is covered in black slime. His cousin Zach tells him that lemon juice will get rid of the black slime. Mitchell decides to spray Grammy s shower half with lemon juice and half with water. After 3 days of treatment there is no change in the appearance of the black slime treated with water but the side with treated with lemon juice the slime is gone. 1. What was the initial observation? Black slime on shower doors 2. Identify the Control Group. Shower side receiving water 3. Independent Variable (what I change) Lemon juice 4. Dependent Variable (what I observed) Amount of Black slime 5. What should Mitchell s conclusion be? The lemon juice did remove the black slime on half of the shower door in 3 days. Now we have introduced variables, let s see if you can find the variables in the next scenario. A burning candle is your next task. You can figure out the candle by its weight, length, diameter, and time of burning, all of these are variables because they can change, a candle from new to one that has burned. Design an experiment that allows you to make comparisons on four candles. Identify your controls and your variables. What is your hypothesis including your variables. Identify procedures, materials, and conduct the experiment. Record your observations and data. Complete this with your conclusion. 1. Purpose: 2. Hypothesis: 3. Variables: 4. Controls: 5. List materials: 6. Write out procedures for experiment: 7. Experiment: 8. Record your observations, data, graph, table, or diagram to organize your information: 9. Conclusion: 4

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8 CHAPTER 2 Measurement Scientist use measurement when they are doing experiments. In the US we use two different measurements. Standard measurement is what you are familiar with, inches, yards, miles, etc. Now in the Scientific community there is a special measurement called metric this is also known as the International System of Units (SI).

9 SECTION 1 Standard Unit and Conversions The International System is the common language that all Scientist use all over the world. In order to use the metric system we have to convert the standard system into metric. The following is how to convert each measurement into metric. Length is the first which is based on multiples of 10 which is called meter (m) in the SI system Common SI Prefixes Prefix Symbol Meaning Kilo k 1,000 Hecto h 100 Deka da Deci d Centi c Milli m (one tenth) 0.01 (one hundredth) (one thousandth) Mass is a measure of the amount of matter that an object contains. The basic SI unit for matter is kilogram (kg). In order to find the mass of an object you will need a triple beam scale to find the mass. 8

10 Weight is a measure of the force of gravity acting on an object. Weight is also a standard measurement. Volume is the amount of space an object takes up. Scientist use volume to measure liquids that they need in experiments. Volume is known as liters in the SI units. To measure volume you will need a graduated cylinder. At the curve of the liquid in the graduated cylinder that curve is called the meniscus. When you read a graduated cylinder you look for the meniscus and write down the reading. Density is the measure of how much mass is contained in a given volume. In order to find the density of an object you will have to use the following formula. Density = Mass / Volume To calculate divide the mass by the volume. Because you are working with two units of measure density is expressed as grams per cubic centimeter (g/cm3), another example is grams per milliliter (g/ml). Time is measured in second (s) in the SI unit of measurements. This is easily divided by multiples of 10, like the other SI units we have used. Example is a millisecond (ms) is one thousandth of a second. Common Conversions for Time 1 s = 1,000 ms 1 min = 60 s 1 h = 60 min Temperature is measured in the units of Celsius. Sometimes Scientist uses another scale of temperature called Kelvin (K) which is the SI unit of temperature. Common Conversion Scale of Temperature 0 C = 273 K 100 C = 373 K Measurement Many Scientist have to measure length, which is done in the metric system. Remember the international system of measurement is the metric system. We will now show how to find the conversion of each length. 1 centimeter (cm) = 10 millimeters (mm) 1 meter (m) = 100 cm =1,000 mm 1 kilometer (km) = 1,000 m Remember, multiply to change larger units to smaller units, and divide to change smaller units to larger units. Convert Millimeters to Centimeters 247mm cm = mm = 24.7cm Convert Centimeters to Meters 39.8 cm = m = cm =

11 Convert Kilometers to Meters 4.38 km = m ,000 = 4, km = 4,380 m Now try these 3 problems: mm cm Review: cm m mm cm cm m cm m km m mm cm km m km m mm cm km m cm m mm cm 10

12 CHAPTER 3 Graphs In Science, scientists sometimes have to use graphs to explain their data.

13 SECTION 1 Types of Graphs Slope is when a line graph is linear. To determine the slope which is the steepness of the graph is to use the slope formula. Slope = Rise/Run = y2 - y1 / X2 - x1 Now, think of a graph as a picture of your data. Line graphs are what Scientists focus their data on in their experiments. Line graphs are used to compare variables. Plotting a line graph; the x axis is horizontal and the y axis is vertical. The horizontal axis shows the manipulated variable. The vertical axis shows the responding variable. Your scale of each axis is designed to span from the smallest value to the largest that will be shown. A point on the graph for each piece of data is a coordinate data point on the graph. A line connecting the data points is a trend. A title explains what the graph shows. Scientists sometimes have to demonstrate their answers in the form of a graph. There are many types of graphs that can be used. We will look at the ones that are used the most. Using a line graph, will display data to show how one variable changes (the responding variable) in response to another variable (the manipulated variable) All graphs have an x-axis and a y-axis. 12

14 Plotting a line graph: A horizontal axis : or x-axis and a vertical axis or y-axis. The horizontal axis is the graph line that runs left to right and is always positive. The vertical axis is the graph line that runs up and down. The point where the two axis cross is the origin. Labels for the axis: the horizontal axis shows the manipulated variable. The vertical axis shows the responding variable. A point on the graph: for each piece of data is represented by a coordinate pair of numbers used to represent a point on a graph. A line connecting the points: The line shows the trend of the data. A title: Explains what the graph shows Type of graphs: Your first choice is to determine which type of graph would best communicate your findings. Your basic choices are bar graph, line graph, pie chart, or scatter plot. BAR GRAPH This is the most common type for science fair projects. You may select a bar graph when your independent variable is qualitative (categories) or quantitative (numbers). An example of a bar graph 13

15 An example of a line graph Again double check the axes Look closely and make sure your bar graph has all the highlighted parts: Independent variable may be qualitative or quantitative LINE GRAPH This is the second most common, but frequently used incorrectly, so be careful here. You should only select a line graph if your independent variable is quantitative (numbers) and you hypothesized that the changes in the independent variable would result in changes in the dependent one. For example, line graphs are great for showing changes in the dependent variable over time or distance along a transect. 14

16 Independent variable MUST be quantitative PIE CHART Pie charts are good for projects that have qualitative independent variables and have generated data that can be expressed as percentages of the total. For example, if your data were counts (i.e. the number of times something happened), then this might be your best choice to compare different treatments. SCATTER PLOT If the purpose is to see if the variables are related (common in environmental projects), but there was not a clear choice for independent and dependent variables (for example wind speed and water temperature), then a scatter plot would be your best choice. This option typically requires much more data than the others to observe a trend. An example of a pie chart Scatter plots are also called X-Y plots 15

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