TEACHER & LESSON PLAN NOTES:
Go over forces lab o Use the Student Graph Discussion Template and have students insert their data from yesterday's experiment. o Discuss why our graphs look so weird and inconsistent o Go over experimental errors o Do "Flicking Masses Lab" o Have students insert in their new data and go over new lab results o Point out a more conclusive set of data/trends etc. o Have them hypothesize why larger masses seem to go less further o Usually, they will say that it's because it's more heavier, has something to do with gravity and weight, and some may even say that it has to do with more atoms. o Discuss if they think the results would be different in a weightless environment w. no table - out in space. o Prep video at 1:50 and point out the two balls of different mass. o Before playing the video, take a poll to see who thinks which ball will win - or if both will go at the same speed. o Play video and discuss the results. Further the discussion with the notes below. Force = Mass x Acceleration o Force = Push/Pull o Mass is the object made of matter. Matter is made of atoms. Matter also has another property - called inertia. Inertia is the resistance to a change in direction, which is a resistance to the push or pull. o Inertia is Newtons first law. Simply stated, "an object at rest will stay at rest unless acted upon by another force. An object in motion will stay in motion unless acted upon by another force." o Point out the books in the skateboard lab and how it appeared that they moved backwards - when in reality, the skateboard and box moved forward until the box hit the books - and forced it to move forward. o Point out that as the number of books increased, the person began to more noticeably move backwards after they pushed the skateboard with books. o Point out that friction was the force that slowed the books and skateboard down. Introduce more about Force, Mass & Acceleration o Forces units o Newton = kg x m/s2 o Newton’s o Scale – force meter |
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Identifying experimental errors
Below is the data from yesterday's lab concerning books pushed in a box. As you can see, the trends are all over the place. Therefore, we cannot officially conclude that there is a causal relationship between mass and the distance the object moves after it has been pushed. There are way too many experimental errors. Some of the experimental errors may have included:
- Pushing the box harder vs. softer
- Measuring wrong
- Putting in the data in the computer wrong
- The skateboard & bearings not functioning the same every time
- The skateboard turning
- The skateboard bumping into things
- The way the books moved after it was pushed
Flicking Masses Lab
In this simple experiment - students flick different sized masses across the table and see how far they go.
Question: How does the mass of the object affect the distance the object goes after it has been flicked?
Materials:
Question: How does the mass of the object affect the distance the object goes after it has been flicked?
Materials:
- Different masses from the mass set
- 2 Meter Sticks
Watch the play by play of each experiment with these two groups. If you were absent - take the data they got from their experiment and put it in your data table.
Notice in the photos how the larger mass didn't move very far and the smaller mass moved very far. Here is a class data table. Use this data for your data table if you were absent. Notice the relationship between mass and distance. As you increase the mass, the less distance it goes.
Question: Based on the data, why is it that as you increase the mass, the distance it goes - decreases?
What is your hypothesis?
Many students hypotheses include some of the following:
To test these hypotheses out - we're going to run an experiment in space - where there is little or no weight, gravity and friction. We have a wooden ball and a brass ball. Pedro, the astronaut will blow on the two balls to see which one will move faster. (On the first film, fast forward it to minute 1:50 to see the experiment).
What do you predict will happen?
What is your hypothesis?
Many students hypotheses include some of the following:
- It has something to do with weight which increases friction.
- It has something to do with gravity pushing down that makes it harder to move it.
- It has something to do with an increased amount of atoms.
- It has something to do with friction.
- It has something to do with it being heavier.
To test these hypotheses out - we're going to run an experiment in space - where there is little or no weight, gravity and friction. We have a wooden ball and a brass ball. Pedro, the astronaut will blow on the two balls to see which one will move faster. (On the first film, fast forward it to minute 1:50 to see the experiment).
What do you predict will happen?
- The brass ball will go faster
- The wooden ball will go faster
- They both will go at the same speed.
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In this video - ff to about 1:57 minutes to see the three balls blown. Notice the brass ball is left behind in a constantly falling, weightless simulating, friction free environment. The reason why the balls move at different velocities is because of its inertia due to the amount of mass the object has.
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Near the end of this video, students test the inertia of different items. Watch how the objects either stay put or keep moving based on their motion.
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In the film, you will notice that the brass ball stayed behind and the wooden ball took off. Because the wooden ball had little mass, it also has less atoms that is pushed to get it moving. (Remember, it is considered weightless in this free falling micro-gravity environment).
Remember, and object is made of mass. Mass is made of matter. Matter is made of atoms. But matter has another property - inertia! Inertia is the property of matter that resists the pushing and pulling of the force. Think about it - which is easier to get moving? A motorcycle, an SUV or a diesel truck full of goods? It's easy to figure thins one out - its simply the motor cycle - because the motor cycle has less atoms to push around - therefore, it has less inertia.
Perhaps you have heard inertia phrased this way: "an object at rest, will stay at rest, unless acted upon by another force. An object in motion will stay in motion unless acted upon by another force."
The whole point of this experiment is to see how inertia plays a critical part in how forces interact with an objects motion.
Remember, and object is made of mass. Mass is made of matter. Matter is made of atoms. But matter has another property - inertia! Inertia is the property of matter that resists the pushing and pulling of the force. Think about it - which is easier to get moving? A motorcycle, an SUV or a diesel truck full of goods? It's easy to figure thins one out - its simply the motor cycle - because the motor cycle has less atoms to push around - therefore, it has less inertia.
Perhaps you have heard inertia phrased this way: "an object at rest, will stay at rest, unless acted upon by another force. An object in motion will stay in motion unless acted upon by another force."
The whole point of this experiment is to see how inertia plays a critical part in how forces interact with an objects motion.