4. What is science? Science is a way to learn about the natural world

5. What do scientists do? Scientists observe, investigate and try to solve problems In their work, scientists use a scientific method

6. Steps of scientific method 1. State the problem 2. Gather information 3. Form a hypothesis 4.Test the hypothesis (conduct experiment) 5. Analyze data 6. Draw conclusions Hypothesis not supported Hypothesis supported Modify hypothesis Repeat several times

7. What is a hypothesis? A hypothesis is a possible explanation for a problem using what you know and what you observe One way of testing a hypothesis is to perform an experiment What is an experiment? An experiment tests the effect of one thing on another using controlled conditions

8. Elements of scientific experimentation An experiment contains the following elements: variables, constants and controls. What is a variable? A variable is a quantity that can have more than a single value. An experiment usually contains at least two variables: dependent variable and independent variable

9. Elements of scientific experimentation Dependent variable: (the variable its value changes according to the changes in the other variables) Independent variable: (The variable you change to see how it will affect the dependent variable)

10. Elements of scientific experimentation Example: In the experiment of measuring the influence of different quantities of fertilizer on plant growth: 1- What are the two variables in the experiment? 2- Which is the dependent variable? 3- Which is the independent variable? Solution: 1- The two variables are: quantity of fertilizer and plant growth. 2- The dependent variable is plant growth. 3- The independent variable is quantity of fertilizer.

11. Elements of scientific experimentation What is a constant? A constant is a factor that does not change when other variables change. What is a control? A control is the standard by which the test results can be compared

12. Elements of scientific experimentation Example: In the experiment of measuring the effect of quantity of fertilizer on plant growth: 1- What other variables should be constants. 2- what could be a control of the experiment. Solution: 1- Amount of water, Amount of light, kind of soil, plant type and room temperature. 2- A plant with no fertilizer added to it

13. Using models in science What is a model in science? (A model is a representation of an idea, event or object to help people understand it better) Models help us to see very large or very small things and how they work.

14. Scientific Theories and Laws What is a scientific theory? A scientific theory is an explanation of things or events based on knowledge gained from many observations and investigations. - A theory is a result of a hypothesis which is supported by many investigations - A theory could be changed with time

15. Scientific Theories and Laws What is a scientific law? A scientific law is a statement about what happens in nature and that seems to be true all the time. - A scientific law does not explain why or how something happens. - Scientific laws are repeated patterns in nature. Theories attempt to explain how and why these patterns develop.

16. Science and Technology Science and technology are not the sam e What is technology? Technology is the application of science to help people. Remember: Science is a way to learn about natural world. Examples of technology includes: computers, mobile phones, cars, planes, microscopes, …….

17. Homework in the Notebook Write the meaning of each of the following 1- Science. 2- Hypothesis. 3- Experiment. 4- Variable. 5- Dependent variable. 6- Independent variable. 7- Constant. 8- Control. 9- Model. 10- Scientific theory. 11- Scientific law. 12- Technology.

18. Quiz 2 Thursday 06/10/2011 Chapter1 – Section 2 Standards of measurement