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- » Scratch directions not consistent with trigonometry

- MalinC
- Scratcher

8 posts

### Scratch directions not consistent with trigonometry

I'm a new Scratcher and I realize that Scratch isn't mainly made for teaching mathematics, but since I'm interested in using it precisely for that, I must raise some questions about the unconventional way Scratch handles directions. When it comes to the coordinate system, Scratch uses a regular Cartesian coordinate system, as opposed to a computer based coordinate system. I guess that Cartesian coordinates are used so that children can learn about them, since that is the convention in school mathematics. So why isn't the same line of reasoning applied to directions? If the Scratch-directions would follow conventions, Scratch would be an excellent tool for introducing trigonometry.

- dracae
- Scratcher

1000+ posts

### Scratch directions not consistent with trigonometry

Yep, the directions and angles are all wonky and strange… I'm a new Scratcher and I realize that Scratch isn't mainly made for teaching mathematics, but since I'm interested in using it precisely for that, I must raise some questions about the unconventional way Scratch handles directions. When it comes to the coordinate system, Scratch uses a regular Cartesian coordinate system, as opposed to a computer based coordinate system. I guess that Cartesian coordinates are used so that children can learn about them, since that is the convention in school mathematics. So why isn't the same line of reasoning applied to directions? If the Scratch-directions would follow conventions, Scratch would be an excellent tool for introducing trigonometry.

- kayybee
- Scratcher

1000+ posts

### Scratch directions not consistent with trigonometry

Yeah, I've tried to use trig and it's really hard.

I've found that you just have to do 90-direction to get the trig angle you want.

(Note: Scratch supports any angle, allowing coterminal angles, so you don't have to find one within the range they wrote in the point in direction block.

I've found that you just have to do 90-direction to get the trig angle you want.

(Note: Scratch supports any angle, allowing coterminal angles, so you don't have to find one within the range they wrote in the point in direction block.

- kayybee
- Scratcher

1000+ posts

### Scratch directions not consistent with trigonometry

Don't forget that scratch goes clockwise but trig goes counter. Just subtract 90 degrees for your calculations.

- MalinC
- Scratcher

8 posts

### Scratch directions not consistent with trigonometry

Yes, you must do two things, since it starts at the wrong place and moves in the wrong direction.

Considering how many students have a hard time remembering how sine/cosine are related to the y-axis/x-axis, I would hesitate to do anything with trigonometry using Scratch in education. It would have been a nice tool for introducing sine/cosine, since trigonometry appears naturally when turning things around, but as it is now, I would swap to another program before explaining the math.

Considering how many students have a hard time remembering how sine/cosine are related to the y-axis/x-axis, I would hesitate to do anything with trigonometry using Scratch in education. It would have been a nice tool for introducing sine/cosine, since trigonometry appears naturally when turning things around, but as it is now, I would swap to another program before explaining the math.

- MalinC
- Scratcher

8 posts

### Scratch directions not consistent with trigonometry

What system is Scratch's direction based on anyways!?

I have also wondered about that. A clock maybe. I don't know.

- kayybee
- Scratcher

1000+ posts

### Scratch directions not consistent with trigonometry

That would be extremely confusing for new Scratchers.Meh…What system is Scratch's direction based on anyways!?

I have also wondered about that. A clock maybe. I don't know.

Oooh!

Maybe there should be multiple settings for how the directions work, like how there is multiple settings for rotation!

- dracae
- Scratcher

1000+ posts

### Scratch directions not consistent with trigonometry

Well, the current direction system is pretty confusing too.That would be extremely confusing for new Scratchers.Meh…What system is Scratch's direction based on anyways!?

I have also wondered about that. A clock maybe. I don't know.

Oooh!

Maybe there should be multiple settings for how the directions work, like how there is multiple settings for rotation!

- NoxSpooth
- Scratcher

1000+ posts

### Scratch directions not consistent with trigonometry

Changing the current system will affect every single project that uses it. Imagine how hard it would be to fix them all…Well, the current direction system is pretty confusing too.That would be extremely confusing for new Scratchers.Meh…What system is Scratch's direction based on anyways!?

I have also wondered about that. A clock maybe. I don't know.

Oooh!

Maybe there should be multiple settings for how the directions work, like how there is multiple settings for rotation!

- dracae
- Scratcher

1000+ posts

### Scratch directions not consistent with trigonometry

Yeah, I know.Changing the current system will affect every single project that uses it. Imagine how hard it would be to fix them all…Well, the current direction system is pretty confusing too.What system is Scratch's direction based on anyways!?

I have also wondered about that. A clock maybe. I don't know.

Oooh!

Maybe there should be multiple settings for how the directions work, like how there is multiple settings for rotation!

I had an idea: Maybe there should be multiple settings for how the directions work, like how there is multiple settings for rotation

But apparently it's too confusing?

- roijac
- Scratcher

100+ posts

### Scratch directions not consistent with trigonometry

probablyYeah, I know.Changing the current system will affect every single project that uses it. Imagine how hard it would be to fix them all…What system is Scratch's direction based on anyways!?

I have also wondered about that. A clock maybe. I don't know.

Oooh!

Maybe there should be multiple settings for how the directions work, like how there is multiple settings for rotation!

I had an idea: Maybe there should be multiple settings for how the directions work, like how there is multiple settings for rotation

But apparently it's too confusing?

you can use the term ((90 - direction) mod (360))

- dracae
- Scratcher

1000+ posts

### Scratch directions not consistent with trigonometry

Meh… That's so much work.probablyYeah, I know.What system is Scratch's direction based on anyways!?

I have also wondered about that. A clock maybe. I don't know.

Oooh!

Maybe there should be multiple settings for how the directions work, like how there is multiple settings for rotation!

I had an idea: Maybe there should be multiple settings for how the directions work, like how there is multiple settings for rotation

But apparently it's too confusing?

you can use the term ((90 - direction) mod (360))

Especially since it's a fix for a direction system that's strange anyways.

- kayybee
- Scratcher

1000+ posts

### Scratch directions not consistent with trigonometry

You don't need the modulus function. probably

you can use the term ((90 - direction) mod (360))

- Failord
- Scratcher

1000+ posts

### Scratch directions not consistent with trigonometry

I made a project that doesn't use trig, but I did manage to come up with a formula for cranking correct angles out of the system. I think it's fine the way it is.

The project…

If you're trying to teach this, script a directional translator. It might be really compex, but it can be done.

The project…

If you're trying to teach this, script a directional translator. It might be really compex, but it can be done.

Thanks for the ride, Scratch Team and community! Unfortunately, the time has come for me to move on from Scratch, so I'll no longer be using the forums. Thanks again, and farewell!

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For old time's sake, see the revolutionary Laser Battle 2.0! Also see Unstoppable Game!

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- MalinC
- Scratcher

8 posts

### Scratch directions not consistent with trigonometry

I do not have a problem with switching between different conventions. It is not about me handling trigonometry in Scratch, but 12-year-old Scratchers.

In my opinion, Scratch would have been an excellent tool for introducing trigonometry using the unit-circle definition, if it had followed mathematical convention. As it is now, any such introduction would have to focus on how to handle the wrong starting point in Scratch (north), and the wrong direction (clockwise). And suddenly it is not that much about trigonometry but more about arithmetics - an excellent teaching/learning opportunity getting obscured by arithmetics.

Furthermore, if you are a 12-year-old Scratcher, wanting to learn trigonometry. And if you do a search on “trigonometry” in Scratch. You will see how all those that know how to handle trigonometry the Scratch-way, use sine on the x-axis and cosine on the y-axis. For those of us that know mathematics, we know that this is mathematically wrong, even if it is a clever work-around in Scratch. But for a 12-year-old Scratcher…

In my opinion, Scratch would have been an excellent tool for introducing trigonometry using the unit-circle definition, if it had followed mathematical convention. As it is now, any such introduction would have to focus on how to handle the wrong starting point in Scratch (north), and the wrong direction (clockwise). And suddenly it is not that much about trigonometry but more about arithmetics - an excellent teaching/learning opportunity getting obscured by arithmetics.

Furthermore, if you are a 12-year-old Scratcher, wanting to learn trigonometry. And if you do a search on “trigonometry” in Scratch. You will see how all those that know how to handle trigonometry the Scratch-way, use sine on the x-axis and cosine on the y-axis. For those of us that know mathematics, we know that this is mathematically wrong, even if it is a clever work-around in Scratch. But for a 12-year-old Scratcher…

*Last edited by MalinC (July 3, 2013 13:38:21)*

- kayybee
- Scratcher

1000+ posts

### Scratch directions not consistent with trigonometry

I'd love to switch to trig angles too, but if we do, then we break either all the projects that already use te old system, or all the projects that made the workaround for trig angles.

And if we leave those there, and use trig angles for new projects, tons of new scratchers or anyone who don't read the announcements will get confused, especially because old projects aren't consistent with the way they changed to.

Any other ideas then?

And if we leave those there, and use trig angles for new projects, tons of new scratchers or anyone who don't read the announcements will get confused, especially because old projects aren't consistent with the way they changed to.

Any other ideas then?

- dracae
- Scratcher

1000+ posts

### Scratch directions not consistent with trigonometry

What are your thoughts on what I suggested? I'd love to switch to trig angles too, but if we do, then we break either all the projects that already use te old system, or all the projects that made the workaround for trig angles.

And if we leave those there, and use trig angles for new projects, tons of new scratchers or anyone who don't read the announcements will get confused, especially because old projects aren't consistent with the way they changed to.

Any other ideas then?

Two options for angles, similar to the options for rotation.

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