jinhusong
Member
Posts: 101
Joined: March 16th, 2017, 3:34 pm
Division: C
State: CA
Location: Santa Clara

Similar stuff here:

A kid uses wire loop to hang a weight on the horizontal screw. When the screw rotates, the wire loop will move to the end of screw and drop to trigger something.

I told him that you may have difficulty to convince the ES that your screw is pushing the wire loop, maybe you can make the wire loop thicker into a something looks like a nut.

Jinhu

Stestra00
Member
Posts: 1
Joined: January 27th, 2019, 11:20 am

What do they catagorize as a screw? Is it the simple machine definition, or the standard definition?

Member
Posts: 159
Joined: March 18th, 2017, 5:14 pm
State: -
Location: Somewhere over the rainbow

Stestra00 wrote:What do they catagorize as a screw? Is it the simple machine definition, or the standard definition?

I’d guess the simple machine definition, but to be safe, I’d use something that is labeled as a screw by the manufacturer.

Shr3D
Member
Posts: 10
Joined: October 28th, 2017, 4:42 pm
Division: C
State: FL
Location: USA

What I have for my screw task is I have looped a string around the screw twice, have one end attached to a weight pulling down, and another end to an object on a ledge/platform. When the weight falls, it turns to screw and pulls the object off the ledge/platform. Would this work for this task?
Science Olympian since 2015 - present
Events this year: MP, BM, WS

Member
Posts: 159
Joined: March 18th, 2017, 5:14 pm
State: -
Location: Somewhere over the rainbow

Shr3D wrote:What I have for my screw task is I have looped a string around the screw twice, have one end attached to a weight pulling down, and another end to an object on a ledge/platform. When the weight falls, it turns to screw and pulls the object off the ledge/platform. Would this work for this task?

How exactly are you pulling the object on the platform?

C8H10N4O2!
Member
Posts: 44
Joined: October 4th, 2018, 3:55 pm
State: -

Shr3D wrote:What I have for my screw task is I have looped a string around the screw twice, have one end attached to a weight pulling down, and another end to an object on a ledge/platform. When the weight falls, it turns to screw and pulls the object off the ledge/platform. Would this work for this task?

I would wrap the screw more than 2 times... It is a minimum that it turns twice, but the more turns it does, the more predictable, and less exact you need to be (also, it saves you a potential touch)

jinhusong
Member
Posts: 101
Joined: March 16th, 2017, 3:34 pm
Division: C
State: CA
Location: Santa Clara

C8H10N4O2! wrote:
Shr3D wrote:What I have for my screw task is I have looped a string around the screw twice, have one end attached to a weight pulling down, and another end to an object on a ledge/platform. When the weight falls, it turns to screw and pulls the object off the ledge/platform. Would this work for this task?

I would wrap the screw more than 2 times... It is a minimum that it turns twice, but the more turns it does, the more predictable, and less exact you need to be (also, it saves you a potential touch)

Also it needs to move the object 2 cm before trigger next action.

C8H10N4O2!
Member
Posts: 44
Joined: October 4th, 2018, 3:55 pm
State: -

jinhusong wrote:
C8H10N4O2! wrote:
Shr3D wrote:What I have for my screw task is I have looped a string around the screw twice, have one end attached to a weight pulling down, and another end to an object on a ledge/platform. When the weight falls, it turns to screw and pulls the object off the ledge/platform. Would this work for this task?

I would wrap the screw more than 2 times... It is a minimum that it turns twice, but the more turns it does, the more predictable, and less exact you need to be (also, it saves you a potential touch)

Also it needs to move the object 2 cm before trigger next action.

But it does, right? It pulls the object off the ledge, which then probably moves more. I dont like this rule because it never says the screw has to directly 'initiate' the next action, which implies that it indirectly can...

jinhusong
Member
Posts: 101
Joined: March 16th, 2017, 3:34 pm
Division: C
State: CA
Location: Santa Clara

C8H10N4O2! wrote:
jinhusong wrote:
C8H10N4O2! wrote:I would wrap the screw more than 2 times... It is a minimum that it turns twice, but the more turns it does, the more predictable, and less exact you need to be (also, it saves you a potential touch)

Also it needs to move the object 2 cm before trigger next action.

But it does, right? It pulls the object off the ledge, which then probably moves more. I dont like this rule because it never says the screw has to directly 'initiate' the next action, which implies that it indirectly can...

My understanding, the screw has to pull the object 2 cm before the object fell off the ledge.

C8H10N4O2!
Member
Posts: 44
Joined: October 4th, 2018, 3:55 pm
State: -

jinhusong wrote:
C8H10N4O2! wrote:
jinhusong wrote:
Also it needs to move the object 2 cm before trigger next action.

But it does, right? It pulls the object off the ledge, which then probably moves more. I dont like this rule because it never says the screw has to directly 'initiate' the next action, which implies that it indirectly can...

My understanding, the screw has to pull the object 2 cm before the object fell off the ledge.

I have a screw holding an object in place on a ledge, the screw rotates (moves less than 2 cm), and the object falls, mostly by force of gravity. It depends on how you explain it, but MIT, my state ES, and Cornell all had no problems with it.

oofboy69
Member
Posts: 4
Joined: January 21st, 2018, 7:20 pm
State: -

What if the screw doesnt actually move at all, but rotates in place, using its threads to move a platform that it is screwed into more than 2cm?

nicholasmaurer
Coach
Posts: 354
Joined: May 19th, 2017, 10:55 am
State: OH
Location: Solon, OH

oofboy69 wrote:What if the screw doesnt actually move at all, but rotates in place, using its threads to move a platform that it is screwed into more than 2cm?

The rule only requires the object to move 2 cm, not the screw itself.
Assistant Coach and Alumni ('14) - Solon High School Science Olympiad
Tournament Director - Northeast Ohio Regional Tournament

Opinions expressed on this site are not official; the only place for official rules changes and FAQs is soinc.org.

C8H10N4O2!
Member
Posts: 44
Joined: October 4th, 2018, 3:55 pm
State: -

nicholasmaurer wrote:
oofboy69 wrote:What if the screw doesnt actually move at all, but rotates in place, using its threads to move a platform that it is screwed into more than 2cm?

The rule only requires the object to move 2 cm, not the screw itself.

I know that this was discussed earlier, but a recent FAQ (maybe national clarification) has stated that the screw is NOT the object.

Shr3D
Member
Posts: 10
Joined: October 28th, 2017, 4:42 pm
Division: C
State: FL
Location: USA

Ok so my screw task was like this:

There was a ball being pulled by a string, which was rotated around the screw. The screw rotated when a mass was dropped and rotated the screw... which then roasted the string pulling on the ball... it kinda worked like a pulley yet did what was said in the rules. Although, I went to a competition and there I didn’t get points for it since the screw needs to work like its simple machines definition: it needs to be rotated and then needs to push an object as it rotates.

Hope this helps!
Science Olympian since 2015 - present
Events this year: MP, BM, WS

knightmoves
Member
Posts: 99
Joined: April 26th, 2018, 6:40 pm
State: -

C8H10N4O2! wrote:I have a screw holding an object in place on a ledge, the screw rotates (moves less than 2 cm), and the object falls, mostly by force of gravity. It depends on how you explain it, but MIT, my state ES, and Cornell all had no problems with it.

I'm surprised by this.

"clearly rotate a screw at least two full rotations so that it operates as a screw converting rotational force into linear force and moves an object at least 2 cm before that object initiates the next action."

I read that as saying that the object must be moved 2 cm by the linear force provided by the screw. In your example, the object is moved a short distance by the screw action, and then falls. So I don't think it is true to say that your screw "moves an object at least 2 cm".