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

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

What do scientists do?Scientists observe, investigate and try to

solve problems

In their work, scientists use a scientific method

Steps of scientific method1. 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

• 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

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

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)

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.

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

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

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.

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

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.

Science and Technology• Science and technology are not the same

• 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,

…….

Homework in the Notebook Write the meaning of each of the following1- 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.

Quiz 2Thursday 06/10/2011

Chapter1 – Section 2Standards of measurement