Begin the analysis of the experiment by asking students to summarize the experiments they conducted in the lab and the purpose of those experiments. The following questions may be helpful in promoting student discussion:

Can you remember the two main questions we wanted to investigate in the lab? What were they? The two questions students were given before beginning the lab were: Can all states of matter exert force? Does the mass of a load affect the force exerted to lift the load?

Can you summarize the types of experiments that you performed in order to answer these questions? Students placed three states of matter in a bucket and hung the bucket on a spring scale in order to determine whether all states of matter exert force. Students lifted loads of different masses to determine whether the mass of a load changed the force exerted to lift it.

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Continue the discussion by posing the following questions.

What types of measurements did you make in your experiments? Students measured distance when lifting the loads, the mass of several loads, and the force exerted on several loads. The distance was measured in centimeters, mass in grams, and force in newtons.

What is similar about a gram, a centimeter or meter, or a newton? They are all considered units of measurement.

Why do we need different types of measurement? They are needed so that we can differentiate between what is being measured.

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Ask students: How can we organize the data from the experiments in order to analyze the data and answer the two main questions? Student answers will vary.

Work with students to develop a table that will organize their data. If necessary, remind students of steps they need to take into consideration as they create and complete a data table:

• Is there a question I need to answer?

• What type of results or measurements did I obtain?

• Which results or measurements could help me answer my question?

• Did I conduct one trial or many trials?

• Did I measure or record the same type of data for each trial?

• How could I arrange a table to show the data I recorded for each trial?

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Draw a data table on the board as you incorporate student suggestions. One example of how the table can be organized is shown on this slide.

Select the data collected by one group and enter it into the table. The data collected by each group may vary slightly.

As a class, discuss the data entered in the table. Ask students the following questions, and refer to the data in the table on the board as you discuss the responses with the class:

What was considered the load in each of the trials? The bucket was included as part of the load in each of the trials. The load for Trial 1 was a 100 g mass and a bucket, the load for Trial 2 was the 100 ml of water (100 ml = 100 g) and the bucket, the load for Trial 3 was the exhaled air and the bucket, the load for Trial 4 was a 100 g mass and the bucket, the load for Trial 5 was two 100 g masses and the bucket, and the load for Trial 6 was three 100 g masses and the bucket.

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Note: Students may ask why the spring scale not was considered part of the load in their experiments. Although the spring scale is lifted along with the bucket and weight(s), it is not considered part of the load. In this experiment, the spring scale was only able to measure the force exerted on the bucket and weight(s), or what was hanging from the hook of the spring scale. The spring scale was not able to measure the force exerted to lift it. Therefore, it was not considered part of the measurable load. It would, however, be possible to measure the force exerted to lift the spring scale by suspending it from another spring scale. If this were done, the force needed to lift the spring scale could be added as part of the force needed to lift the load.

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Continue asking students questions once the data has been entered into the Data Table:

What was the same about each trial? All six trials moved the load the same distance – 20 cm.

Why do you think the distance was kept the same for each trial? The distance was kept constant because we do not know whether distance will affect the force exerted to lift a load. We wanted to test the effect of changing mass on force and whether all states of matter exert force. For example, if we lifted two states of matter at two different distances and the force changed, we would not know whether the force changed because of the state of matter or the distance. By keeping distance constant, we eliminated this problem.

What could we do to test whether the distance a load is lifted affects force? Student answers will vary. One suggestion would be to lift the same load at different distances and determine the force at each distance. Students will perform this experiment in the next investigation.

What else was similar among some of the trials? All the trials contained a solid object, the bucket. The loads for Trials 1, 4, 5, and 6 all contained an additional object(s), the 100 g masses, that were solids. In Trials 1, 2, and 4, the same amount of force was exerted to lift the load – 1.6 N.

What was different? The load for Trial 2 consisted primarily of liquid and the load for Trial 3 primarily consisted of gas, as compared to the other trials, which consisted of solids. The mass of the loads was different in Trials 4, 5, and 6. The force exerted to lift the loads was different for Trials 1, 2, and 4, as compared to Trials 3, 5, and 6.

Even though you found some differences in the trials, what can you conclude about the states of matter and force? Did all three states of matter exert force? Although the mass of the loads differed or the force exerted on the load differed, our data shows that the solids, liquids, and gases all exerted force or that a force was exerted to lift a load of solids, liquids, or gases.

Direct students to look at the trials in which they measured the mass of the load:

Ask students: Do you observe a pattern between the mass and the force exerted on the load? The weight, or mass, of the load, changed the amount of force needed to lift it. As the mass of a load increased, the force exerted to lift the load increased.

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Point out to students that the experiments where mass was varied were useful in finding out whether or not a Rule existed. 

Discuss with students that putting data in a table makes the relationship easier to see because it is organized. They can see numbers increasing or decreasing as they review the Trials.

Ask Students: Can you use this rule to make predictions about different loads? For example: Which would require more force to lift, a cat with a mass of 400 kg or 600 kg?  600 kg.

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This final slide poses two questions that students will be able to answer once they complete the next Investigation, Understanding Work.

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