Transcript

Designing Experiments Using the

Scientific Method

Key Words

Lesson 1

Scientific Method

Hypothesis

Experiment

Data

Conclusion

Procedure

Variable

Independent Variable

Dependent Variable

Control Group

Experimental Group

TrialExperimental Error

Bias

Notice the color of our key words.

process answers

stepsproblem question

organizededucated guess

information

Identify the problem

Form a Hypothesis

Create an Experiment

Perform an Experiment

Analyze the Data

Modify the Experiment

Conclusion

Let’s use some of our “key words” in an investigation.

First, our procedure. (Step by step plan)I want to know if warmer temps. cause robin eggs to hatch faster?

Variable Control Group Experimental Group

Variable- Factor that affects results of an experiment.

Number of eggs

Temperature

Humidity

Lighting

There are 2 kinds of variables.*Independent Variable-Factor I change to find out what will happen.

*Dependent Variable- Variable affected by changes in independent variable.

Control Group-Group used for comparison. All variables controlled by me.

4

85 degrees

70%

Low Light

Experimental Group-Group exposed to changes in independent variable. Can you see what I changed in this group?

4

97 degrees

70%

Low Light

Every time we repeat this experiment it is called a Trial.

Temperature

How long it takes the eggs to hatch

Do cows cause global warming?

Why was my number different than yours!?

• Maybe it was experimental error?

True value of measurement vs. Measured value

l___________l6 mm l___________l7mm

You measured 6mm. Your lab partner measuredthe same seed at 7mm.

Sunflower Seed

Actual measurement was 6.5 mm. Why?

Human Error

But I want my hypothesis to be right!

Bias is a wish or expectation that your experiment will lead to a certain conclusion.

Let’s watch a clip to better understand Bias.

This kind of thinking can cause Bias.

scientists

observations

hypotheses

experiments

conclusions

results

The Bikini Bottom gang loves science class and wants to do a little research. Read the description for each

experiment and use your knowledge of the scientific

method to answer the following questions.

Flower PowerSpongeBob loves to garden and wants to grow lots of

pink flowers for his pal Sandy. He bought a special Flower Power fertilizer to see if it will help the plants

produce more flowers. He plants 2 plants of the same size in separate containers with the same amount of potting soil. He places one plant in a sunny window

and waters it every day with fertilized water. He places the other plant on a shelf in a closet and waters

it with plain water every day.

What did SpongeBob do wrong in this experiment? Explain.How can he test the effectiveness of the fertilizer?

Set up an experiment that tests this .

Super SnailsGary is not the smartest snail in Bikini Bottom and

believes he can improve his brain power by eating Super Snail Snacks. In order to test this hypothesis, he recruits SpongeBob and several snail buddies to help him with an experiment. The snails eat one snack with each meal every day for three weeks. SpongeBob created a test and gave it to the snails before they started eating the snacks as well as after three weeks.

Based on the data, do the Super Snail

Snack work? Explain.

Set up the experiment and list the procedure he

should use.

Snail Before AfterGary 64% 80%

Larry 78% 78%

Barry 82% 84%

Terry 72% 70%

Bubble Time

Patrick loves bubble gum and would like to be able to blow bigger bubbles than anyone else in Bikini Bottom. To prepare for the Bikini Bottom Big Bubble Contest, he bought five different brands of bubble gum and he needs your help to find the brand that creates the biggest bubbles.

Write an experiment to test the bubble power of the bubble gum brands and

help Patrick win the contest.

Discussion Questions

1. What data would lead scientists to accept the hypothesis in the experiment with the robins’ eggs? What results might lead them to reject the hypothesis? What other variables might affect the results?Using the data table in our notes, write out the procedures that should be included in

this experiment.

A farmer believes that fertilizer runoff from a farm is killing the fish in a nearby pond.

1. Set up an experiment to test his hypothesis. Be sure to include

all the procedures he needs to follow.

The farmer measures the amount of fertilizer in the pond each week and counts the number of dead fish. The measurements indicate that, as the fertilizer concentration increases, the number of dead fish increases.

2. Can the farmer confidently conclude that it must be fertilizer from the farm that

is killing the fish? Why or why not?


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