Here's an animoto video of our rocket project. Turn up the volume and enjoy. The song is Paper Planes by M.I.A. It's a satire about the way people stereotype immigrants, but I think the chorus is perfect for our paper rockets.
Monday, January 26, 2009
Saturday, January 24, 2009
Why do things float or sink?
We have just completed an experiment investigating why things float or sink. Students filled film canisters with various weights. The students found the mass when the film canister sunk, floated, and was at neutral buoyancy. They used water displacement to find the volume of the film canister. Here's the data from 15 of the groups.
Averaging the data we got a mean mass for the sinking items as 50.6. For floating items it was 16.8. For neutral items the mass was 40.5. The average volume we found was 40.2
Students then created a rule based on the data. It appeared that the objects where their mass was greater than their volume, they would float. If the mass was less, it would sink. If it was the same, it would be neutral.
The relationship between mass and volume is called density. It is the key topic we will be studying for the next two weeks.
Averaging the data we got a mean mass for the sinking items as 50.6. For floating items it was 16.8. For neutral items the mass was 40.5. The average volume we found was 40.2
Students then created a rule based on the data. It appeared that the objects where their mass was greater than their volume, they would float. If the mass was less, it would sink. If it was the same, it would be neutral.
The relationship between mass and volume is called density. It is the key topic we will be studying for the next two weeks.
Wednesday, January 14, 2009
Final rocket due tomorrow
Remember to bring your final rocket tomorrow. Here's a video from our last test launch. It wasn't the rocket that went the highest but it landed right next to me so I think that's worth a post.
Monday, January 5, 2009
Inertia demonstrations
Welcome back to school and I hope everyone had a wonderful holiday break. I took my family to the Monterey Bay Aquarium and the California Academy of Sciences.
Just before we left for vacation we filmed demonstrations on inertia. Students created their own demonstrations from objects from home or around the class and wrote a script to explain the demonstrations. Below are three examples. Don't forget to turn up the volume.
In case you can't hear the videos, all objects need to have a net unbalanced force exerted on them in order to speed up, slow down, or change direction. In the first example, the student exerted a force on the index card so it accelerated forward. The washer would have stayed stationary forever, but the absence of the card holding it up meant that there was a net unbalanced force (gravity) that pulled it down. It would have kept falling down forever, but the table exerted a force on it to stop it.
If you want a copy of your video, email me and I'll send it on.
Just before we left for vacation we filmed demonstrations on inertia. Students created their own demonstrations from objects from home or around the class and wrote a script to explain the demonstrations. Below are three examples. Don't forget to turn up the volume.
In case you can't hear the videos, all objects need to have a net unbalanced force exerted on them in order to speed up, slow down, or change direction. In the first example, the student exerted a force on the index card so it accelerated forward. The washer would have stayed stationary forever, but the absence of the card holding it up meant that there was a net unbalanced force (gravity) that pulled it down. It would have kept falling down forever, but the table exerted a force on it to stop it.
If you want a copy of your video, email me and I'll send it on.
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