Lesson 3-Scientific Method G6.pptx

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• Science
• Secondary Education
• Age 12

Unit-1: Being a ScientistLesson 3: The Scientific Method

Text

• Key concept: Relationships

• Related concepts: Evidence and Patterns

• Global context: Scientific and Technical Innovation

• IBLP: Thinkers

• ATL skills:

• 1-Self management/affective skills/practice dealing with disappointment and unmet expectations

• 2-Thinking/creative thinking/make guesses, ask what if questions and generate testable hypotheses.

Lesson Objectives

How is Science done?

• Science starts with an OBSERVATION

• An OBSERVATION can then lead to a QUESTION

• And a scientist will conduct an INVESTIGATION to find the ANSWER

What Is The Scientific Method?

• The scientific method is a series of steps used by scientists to solve a problem or answer a question

• Steps are as follows:

1. Observation / Asking a Question

2. Identify your variables

3. Form a Hypothesis based on research

4. Design a Controlled Experiment

5. Record and Analyze Results

6. Draw Conclusions

Criterion B

Inquiring/Designing

Criterion C

Processing/Evaluating

How Do Scientists Form a Hypothesis?

• A scientist bases his/her hypothesis both on:

• 1-What he/she has observed

• and

• 2-What he/she already knows to be true / scientific research

Example question

• A scientist notices that the tomato plant closest to her neighbor’s yard is much taller than any of the other plants in her garden bed.

• She also notices that the neighbor turns on his sprinkler system every day, and that some of this water reaches only her big plant.

• The scientist creates a question:

• Does daily watering from a sprinkler make a tomato plant grow faster than other tomato plants?

Example hypothesis

• The scientist creates this hypothesis to address her question:

• If the tomatoes in the garden are watered daily, then they will grow faster. This is because tomatoes grow more when they get more water.

What do you do with a hypothesis?

• The hypothesis that a scientist creates leads him or her to make a prediction that can be tested next in an investigation.

• A hypothesis includes a possible explanation about why the expected outcome of a test will occur

Examples of hypotheses…

• A good hypothesis is worded like this:

• If…..then…...because…….

• If students eat a lot of candy, then they will get more cavities because sugar on teeth causes cavities.

• If students eat a lot of chocolate, then they will get a sick stomach because a lot of chocolate all at once is hard for the stomach to digest.

Examples of hypotheses…

• A good hypothesis is worded like this:

• If…..then…...because…….

• If salt is added to a plant’s soil, then the plant will die because salt will dry out the soil so that there is not enough water left for the plant.

• If people spend more time in the sun, then they will be more likely to get skin cancer because too much exposure to ultraviolet light causes skin cancer.

Growing Plants

Naya’s grandmother gave her a plant for her birthday and asked her to take good care of it.

After a few days, Naya noticed that her plant didn’t look so good.

What could be the reason? What do plants need to grow and stay healthy?

Using gizmos “Growing Plants”, try to grow the tallest plant. How did you do that?

Growing Plants-Hypothesis

• After making observations about growing the tallest plant, can you form a hypothesis? What would you like to know more about?

• Example hypothesis: If I increase the number of lights that my plant is exposed to then, the height of my plant will increase because plants need light in order to perform photosynthesis and make their own food.

• Notice that the hypothesis is written in the following format:

• If……..then……because

Types of variables

• Independent variable:

• the one factor that is deliberately changed by the person doing the experiment

• Dependent variable:

• the factor which is measured in the experiment

• Controlled / constant variables:

• all the factors that stay the same in an experiment

Types of variables

• Independent variable:

• the one factor that is deliberately changed by the person doing the experiment

• In the growing plants experiment, we will change the number of lights.

• We will do the experiment with no lights, one light, two lights and three lights.

Types of variables

• Dependent variable:

• the factor which is measured in the experiment

• In the growing plants experiment, we will measure the height of the plant. We will use a ruler to measure the height and the unit of measurement will be cm

Types of variables

• Controlled / constant variables:

• all the factors that stay the same in an experiment

• In the growing plants experiment, we will make sure that these variables are controlled:

• -volume of water (we will add 70ml to each plant)

• -amount of soil added (add 2 cups per plant)

• -amount of fertilizer added (add

• -type of plant used (we will use a tomato plant)

Growing Plants-Variables

IV

DV

Example hypothesis: If I increase the number of lights that my plant is exposed to

then, the height of my plant will increase because plants need light in order to

perform photosynthesis and make their own food.

Identifying the variables in a scientific experiment

• When performing an experiment, scientists need to ensure that the experiment is FAIR.

• What does “FAIR” mean in this situation?

• Some variables need to stay the same throughout the experiment. These are called controlled variables.

A birdy example…

• Imagine you want to see what color of bird feeders your local birds preferred.

• Red? Blue? Green?

Our Constants and Variables

• Independent Variable: color of the feeders

• Dependent Variable: amount of seed eaten

• Constant:

  • the location of the feeders

  • the kind of feeder used

  • Type of seeds

  • putting the feeders out at the same time

• If everything except the independent variable is held constant, we can say:

The experiment is FAIR.

ONLY the independent variable can change!

Is Sam’s experiment fair? YES? NO?

Is Sam’s experiment fair? YES? NO?

If several variables were changed at the same time, the scientist would not know which variable was responsible for the observed results.

What do you think?

• Salma loves birds and wants to see as many as she can in her yard. She wants to know whether she is wasting money buying an expensive mixed seed, when a cheaper brand just arrived at her local store. She wonders… will the expensive seed attract more birds to her backyard?

How would you advise her to find out if the expensive seed is better?

Salma’s Experimental Design

Salma’s Experimental Design

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Lets work on the following worksheet:Identifying Variables