Not light related but a good demo: use a wheel with rubber bands instead of spokes, mount it vertically, and aim a hairdryer at the rubber bands
on
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one side, and the wheel will turn. Maybe next year if the theme is
'heat'?
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A candle flame works as well as a hair dryer, and is a bit less prone to the suspicion they you might be blowing the wheel round.
Hmm...that's an interesting scale up version of the metal foil rotating fan thingies. If that's what you mean. Don't suppose it would take much heat convection to get a bike wheel turning with suitable blades. Think you might need something better than rubber bands.
Explain by a demonstration HOW Scotchlite reflectives work.
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Does anyone know how Scotchlite works by the way?
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If it is somehow a mass of corner reflectors, you could build a big corner reflector from mirrors, and use smoke or a water tank to show the light being bounced back. Really boring demo though. Can also explain about radar reflectors on ships.
As I understand it, Scotchlite is a mass off tiny beads. Being rounded, they can't lose their 'edge'.
On the other hand 'Reflexite' *is* made of corner reflectors. These do lose their edge and old reflexite can perform badly, so check your Sam Browne...
Explain by a demonstration HOW Scotchlite reflectives work.
Quoted message said:
Does anyone know how Scotchlite works by the way?
Quoted message said:
If it is somehow a mass of corner reflectors, you could build a big corner reflector from mirrors, and use smoke or a water tank to show the light being bounced back.
You don't need to do that. If you make a big enough corner reflector to refelct a face then you can see that light always comes straight back because wherever you look at it from you always see your face. -- Chris Malcolm [email hidden] +44 (0)131 651 3445 DoD #205 IPAB, Informatics, JCMB, King's Buildings, Edinburgh, EH9 3JZ, UK ["]http://www.dai.ed.ac.uk/homes/cam/]
Explain by a demonstration HOW Scotchlite reflectives work.
Quoted message said:
Does anyone know how Scotchlite works by the way?
Quoted message said:
If it is somehow a mass of corner reflectors, you could build a big corner reflector from mirrors, and use smoke or a water tank to show the light being bounced back. Really boring demo though. Can also explain about radar reflectors on ships.
As I understand it, Scotchlite is a mass off tiny beads. Being rounded, they can't lose their 'edge'.
On the other hand 'Reflexite' *is* made of corner reflectors. These do lose their edge and old reflexite can perform badly, so check your Sam Browne...
Explain by a demonstration HOW Scotchlite reflectives work.
Quoted message said:
Does anyone know how Scotchlite works by the way?
Quoted message said:
If it is somehow a mass of corner reflectors, you could build a big corner reflector from mirrors, and use smoke or a water tank to show the light being bounced back. Really boring demo though. Can also explain about radar reflectors on ships.
As I understand it, Scotchlite is a mass off tiny beads. Being rounded, they can't lose their 'edge'.
On the other hand 'Reflexite' *is* made of corner reflectors. These do lose their edge and old reflexite can perform badly, so check your Sam Browne...
Explain by a demonstration HOW Scotchlite reflectives work.
Does anyone know how Scotchlite works by the way?
If it is somehow a mass of corner reflectors, you could build a big corner reflector from mirrors, and use smoke or a water tank to show the light being bounced back. Really boring demo though. Can also explain about radar reflectors on ships.
Scotchbrite isn't (and you can use scotch tape as a cheap reflector) but th efree reflectors that nationwide have been handing out to primary schools in scotland are.
Three square mirrors and a laser pointer would do it.. show the light coming back to wherever it was aimed from.
Explain by a demonstration HOW Scotchlite reflectives work.
Does anyone know how Scotchlite works by the way?
If it is somehow a mass of corner reflectors, you could build a big corner reflector from mirrors, and use smoke or a water tank to show the light being bounced back. Really boring demo though. Can also explain about radar reflectors on ships.
Scotchbrite isn't (and you can use scotch tape as a cheap reflector) but th efree reflectors that nationwide have been handing out to primary schools in scotland are.
Three square mirrors and a laser pointer would do it.. show the light coming back to wherever it was aimed from.
Explain by a demonstration HOW Scotchlite reflectives work.
Does anyone know how Scotchlite works by the way?
If it is somehow a mass of corner reflectors, you could build a big corner reflector from mirrors, and use smoke or a water tank to show the light being bounced back. Really boring demo though. Can also explain about radar reflectors on ships.
Scotchbrite isn't (and you can use scotch tape as a cheap reflector) but th efree reflectors that nationwide have been handing out to primary schools in scotland are.
Three square mirrors and a laser pointer would do it.. show the light coming back to wherever it was aimed from.
Not light related but a good demo: use a wheel with rubber bands instead of spokes, mount it vertically, and aim a hairdryer at the rubber bands
on
Quoted message said:
Quoted message said:
one side, and the wheel will turn. Maybe next year if the theme is
'heat'?
Quoted message said:
A candle flame works as well as a hair dryer, and is a bit less prone to the suspicion they you might be blowing the wheel round.
Quoted message said:
Hmm...that's an interesting scale up version of the metal foil rotating fan thingies. If that's what you mean. Don't suppose it would take much heat convection to get a bike wheel turning with suitable blades. Think you might need something better than rubber bands.
Not sure I understand you correctly, but the way the demo I saw works is that the rubber bands stretch when they get warmer, the wheel is offcenter so one side falls down, etcetera.
Not light related but a good demo: use a wheel with rubber bands instead of spokes, mount it vertically, and aim a hairdryer at the rubber bands
on
Quoted message said:
Quoted message said:
one side, and the wheel will turn. Maybe next year if the theme is
'heat'?
Quoted message said:
A candle flame works as well as a hair dryer, and is a bit less prone to the suspicion they you might be blowing the wheel round.
Quoted message said:
Hmm...that's an interesting scale up version of the metal foil rotating fan thingies. If that's what you mean. Don't suppose it would take much heat convection to get a bike wheel turning with suitable blades. Think you might need something better than rubber bands.
Not sure I understand you correctly, but the way the demo I saw works is that the rubber bands stretch when they get warmer, the wheel is offcenter so one side falls down, etcetera.
Not light related but a good demo: use a wheel with rubber bands instead of spokes, mount it vertically, and aim a hairdryer at the rubber bands
on
Quoted message said:
Quoted message said:
one side, and the wheel will turn. Maybe next year if the theme is
'heat'?
Quoted message said:
A candle flame works as well as a hair dryer, and is a bit less prone to the suspicion they you might be blowing the wheel round.
Quoted message said:
Hmm...that's an interesting scale up version of the metal foil rotating fan thingies. If that's what you mean. Don't suppose it would take much heat convection to get a bike wheel turning with suitable blades. Think you might need something better than rubber bands.
Not sure I understand you correctly, but the way the demo I saw works is that the rubber bands stretch when they get warmer, the wheel is offcenter so one side falls down, etcetera.
Scotchbrite isn't (and you can use scotch tape as a cheap reflector) but th efree reflectors that nationwide have been handing out to primary schools in scotland are.
Quoted message said:
Three square mirrors and a laser pointer would do it.. show the light coming back to wherever it was aimed from.
Ummm Scotchbrite is a pan scourer (known in the Shed as a 'green scritcher'😉 as many housewives know.
Scotchbrite isn't (and you can use scotch tape as a cheap reflector) but th efree reflectors that nationwide have been handing out to primary schools in scotland are.
Quoted message said:
Three square mirrors and a laser pointer would do it.. show the light coming back to wherever it was aimed from.
Ummm Scotchbrite is a pan scourer (known in the Shed as a 'green scritcher'😉 as many housewives know.
Scotchbrite isn't (and you can use scotch tape as a cheap reflector) but th efree reflectors that nationwide have been handing out to primary schools in scotland are.
Quoted message said:
Three square mirrors and a laser pointer would do it.. show the light coming back to wherever it was aimed from.
Ummm Scotchbrite is a pan scourer (known in the Shed as a 'green scritcher'😉 as many housewives know.
The sort of thing that would quite rightly be frowned upon nowadays!
Heh, this happened about 1995. I'm only 23!
AFAICR everyone thought it was highly amusing, once the trick had been explained. Most people knew enough about fluoresence anyway to know that it was a trick and even those who had to have the effect explained had a laugh about it. Especially since the teacher explained what powder he'd used and where U.V. lights might be found in the wild...
As has been pointed out by other posters, at least I remember the lesson, unlike half the pointless stuff I did at school. It was perfectly calculated to appeal to the mind of the average wicked schoolboy and girl.
The sort of thing that would quite rightly be frowned upon nowadays!
Heh, this happened about 1995. I'm only 23!
AFAICR everyone thought it was highly amusing, once the trick had been explained. Most people knew enough about fluoresence anyway to know that it was a trick and even those who had to have the effect explained had a laugh about it. Especially since the teacher explained what powder he'd used and where U.V. lights might be found in the wild...
As has been pointed out by other posters, at least I remember the lesson, unlike half the pointless stuff I did at school. It was perfectly calculated to appeal to the mind of the average wicked schoolboy and girl.
Not sure I understand you correctly, but the way the demo I saw works is that the rubber bands stretch when they get warmer, the wheel is offcenter so one side falls down, etcetera.
Oh right. No I misunderstood. I thought you were using the twist in a wide rubber band to rotate the wheel by airflow in the same manner as a propeller. But I see what you mean now. Knew I shouldn't have chucked my old wheels away.
