Lesson 5: Designing an Experiment

Standard VI.1 Matter and Energy: All students will measure and describe things around us; explain what the world around us is made of; identify and describe forms of energy; and explain how electricity and magnetism interact with matter.

Elementary Benchmark 4: Identify forms of energy associated with common phenomena.

 

National Technology Standards:

1. Basic operations and concepts

·        Use keyboards and other common input and output devices (Including adaptive devices when necessary) efficiently and effectively.

5. Technology research tools

·        Use technology tools (e.g. calculators, data collection probes, videos, educational software) for problem solving, self-directed learning, and extended learning activities.

Objective: To introduce students to the scientific method of experimentation. 

 

Materials (for each group)

·        4 different types of batteries (American Fare, Duracell, Energizer, Rayovac)

·        Flashlights

·        Worksheet on scientific method

·        Computers

·        Appleworks software (spreadsheet program)

 

Engage

          I have a problem. I see all these advertisements for batteries and I do not know which ones to buy. I want to get the best brand, the batteries that will last the longest and be the most cost effective. How do I know which company is telling the truth? They can’t all make the best batteries. Today we are going to be scientists; we are going to design an experiment to get to the bottom of this best battery business. 

 

Explore

To test the different types of batteries, we need to set up some kind of experiment. First of all, we have to state a hypothesis, or make an educated guess. Based on what you know about the different types of batteries, which one do you think will last the longest? Think about this for a few minutes, then discuss your ideas with you group members. When the group agrees on which battery will last the longest, record your hypothesis on your worksheet.

The next step is to actually carry out a test to see if your hypothesis is correct. How could you test batteries to find out how long they last? There are many possible ways; the materials we have to work with today are flashlights and four different types of batteries. I have 8 flashlights, there are 2 flashlights for each type of battery. Each battery is numbered 1-8 and I have recorded what kind of batteries are in each flashlight. Over the next couple days, these flashlights are going to be burning constantly, until the batteries die out. I need 8 responsible people who can watch these flashlights all the time. You will take them home with you tonight and bring them back tomorrow morning. It is very important that you do not drop these or open them up at any time. If the light goes out while we are not in school, you need to write the time on the masking tape on the flashlight. Make sure that you include A.M. or P.M. when you write the time. You do not need to stay up all night to watch the light. If you wake up and the light is out, record the time at that point – do it right away because you probably will not remember it when you wake up in the morning.

After the flashlights have been distributed, record who has each flashlight. As a class, turn on the flashlights and record the time. Until the flashlights begin to burn out, we do not have to do anything else for our experiment. At that point, begin to record the times on the chart on the worksheets.

When all the data from the flashlights has been recorded, the groups will calculate the total time for each brand of battery. As you work on finding the total time, remember:

·        From A.M. to P.M. is 12 hours (Example: from 1:30 P.M. to 1:30 A.M. would be 12 hours)

·        From P.M. to P.M. is 24 hours (Example: from 1:30 P.M. on Tuesday to 1:30 P.M. on Wednesday would be 24 hours)

After you have found the total number of hours, record your time on the chart on the board.

          The next step is to enter the data in a spreadsheet using Appleworks. On the computer, go to Appleworks and open up a spreadsheet. In column A, enter the names of the batteries. Move to column B and enter the total time that each battery lasted. Once you have entered this information you will make a bar graph showing the results. To make a graph, highlight all the data on your spreadsheet. Click on the graph button at the top of the screen and choose a bar graph. When you are done with the graph, raise your hand and we will print out your spreadsheet and graph.    

 

Develop

          What did we find out about the different types of batteries? Which brand lasted the longest? (Rayovac) Which brand burned out first? (Energizer) Was there a big difference in how long the different brands lasted?

          Discuss the experiment. Anything that could effect the outcome of the experiment is called a variable. What were some of the variables in this experiment?

·        Expiration dates on batteries

·        Quality of flashlights

·        Type of flashlights (Were they all the same or were some of them different?)

·        Flashlights may have burned out while you were sleeping, so times may not be accurate.

·        Some flashlights were accidentally bumped or dropped, which may have affected the mechanisms in them.

How could we resolve these problems to get more accurate results?

 

Extend/Apply

                The scientific method is a very common way to solve problems. Think about how often you follow these steps in everyday life: you have a problem, so you figure out some things that might be causing your problem. Once you have some possible causes, you try to find out which thing is actually causing the problem and fix it. Give the students an example of a question to be tested, how would they apply the steps of the scientific method to this situation?