# do you know science?

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You throw a blanket over an empty bed. Does it warm up?

Drop a marble from the top of the mast of a fast boat. It lands: i) behind the mast ii) in front of the mast iii) at the foot of the mast

Anybody have any other suchlike examples?

-- Rich

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There have been entire books on this subject. I remember getting one of them as a child from "scholastic books." Asked questions like, "Which weighs more, a pound of feathers or a pound of lead?" I think the books generally go under the broad subject heading of "brain teasers."

Jon

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In the water.

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Which weighs more: a pound of feathers, or a pound of gold?

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In the water.

================================== Since this is a physics newsgroup and the correct answer is iii), you must be one of the many clowns that should be thrown from the yard arm.

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Since it's cross-posted to an _engineering_ group, the answers to both questions are "it depends".

If the bed is in the sun and it is white, and the blanket is dark, then it will warm up with the blanket on it. If it is in the sun and has dark sheets, and the blanket is white, then it will cool down. If it's not in the sun then it'll probably stay at the same temperature, unless there's a cat involved somehow.

If the fast boat is in a vacuum, and it isn't rocking, and the mast is straight up and down, and the marble is given no horizontal velocity, and the marble does not strike anything on the way down, and either the marble isn't a magnet or the mast is not steel, then yes, it'll land at the foot of the mast, unless there's some other confounding factor that you forgot to mention because you were so busy being clever that you forgot to be smart.

```--
Tim Wescott
Wescott Design Services```
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| >> Drop a marble from the top of the mast of a fast | >> boat. It lands: | >> i) behind the mast | >> ii) in front of the mast | >> iii) at the foot of the mast | >>

| >> Anybody have any other suchlike examples? | >>

| >> -- | >> Rich | >

| > In the water. | >

| > ================================== | > Since this is a physics newsgroup and the correct answer is iii), you | > must be one of the many clowns that should be thrown from the yard arm. | | Since it's cross-posted to an _engineering_ group, the answers to both | questions are "it depends". | | If the bed is in the sun and it is white, and the blanket is dark, then | it will warm up with the blanket on it. If it is in the sun and has | dark sheets, and the blanket is white, then it will cool down. If it's | not in the sun then it'll probably stay at the same temperature, unless | there's a cat involved somehow. | | If the fast boat is in a vacuum, and it isn't rocking, and the mast is | straight up and down, and the marble is given no horizontal velocity, | and the marble does not strike anything on the way down, and either the | marble isn't a magnet or the mast is not steel, then yes, it'll land at | the foot of the mast, unless there's some other confounding factor that | you forgot to mention because you were so busy being clever that you | forgot to be smart. |

Adding caveats to the original question doesn't make you clever either. Marbles are glass and not attached to bungee cords, by default. Foot of the mast can still be in front or behind, or port or starboard, unless the mast is hollow - but that would give away the point of the question. And a blanket in the sun is not going to cool because of its colour, and the moggie will choose the pillow unless there is a cardboard box. You were so busy being smart that you forgot to be clever.

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Depends on how many cats.

John

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Only a physicist would throw someone from a yardarm. Anybody else would hang them.

John

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| >> Drop a marble from the top of the mast of a fast | >> boat. It lands: | >> i) behind the mast | >> ii) in front of the mast | >> iii) at the foot of the mast | >>

| >> Anybody have any other suchlike examples? | >>

| >> -- | >> Rich | >

| >In the water. | >

| >================================== | >Since this is a physics newsgroup and the correct answer is iii), you | >must be one of the many clowns that should be thrown from the yard arm. | >

| >

| | Only a physicist would throw someone from a yardarm. Anybody else | would hang them. | Then it wouldn't land in the water, the flies would lay eggs, the eggs would become maggots and eat it and the stink would permeate the ship. Much better if it were food for clown fish.

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The marble will roll under the workbench never to be seen again making the question moot. Art

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| > Drop a marble from the top of the mast of a fast | > boat. It lands: | > i) behind the mast | > ii) in front of the mast | > iii) at the foot of the mast | >

| > Anybody have any other suchlike examples? | >

| > -- | > Rich | | The marble will roll under the workbench never to be seen again | making the question moot. | Art

Nah, the marble is caught under the blanket.

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STUPID QUESTION!

1. You did not say whether the ship was moving.
2. What was the speed and direction of the wind? Absolutely? Relatively?
3. Was the ship rolling or pitching? How much?
4. Was the mast raked?

On and on. It is such niggling details that screw up experiments. Seldom is a situation matching the definite conditions describe in textbooks.

Bill

```--
An old man would be better off never having been born.```
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Of course not. Where could the heat be coming from?

In a vacuum, at constant speed, it will land at the base of the mast. In air, the drag will drop it behind the mast.

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A pound of feathers weighs more, because feathers are weighed using avoirdupois weight, and gold is weighed using troy weight.

That's why they use lead in the teaser.

Hope This Helps!

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Do fast ships ever put into port?

Thanks, Rich

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You mean more questions?..

If you open the fridge door does the room eventually end up hotter or colder?

How do ice skates work?

Whats the other name for Dihydrogen Monoxide?

Does the moon rotate?

Do electrons flow from +ve to -ve or from -ve to +ve?

Why is very old window glass thicker at the bottom?

Why does breathing Helium make your voice sound funny?

How do you seperate a mixture of salt and sand?

If electricity goes around a circuit and returns to the battery.. why does the battery go flat?

If a goat is tied to a fence post on the edge of a circular field..How long must the rope be so that the goat can only eat half the grass?

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In sci.skeptic CWatters wrote: ...

...

I worked on the physics of skates in the 80s. At that point classical theory showed there was no good explanation for how ice actually melted under the skate -- pressure and frictional heating turned out to be insufficient by a significant margin.

I left the group as they started to get into the quantum physics of steel-on-ice.

I noticed someone is claiming to have found an explanation:

```--
[Not a farmer:]
[Aussie wheat production is trending higher, but yield is declining]```
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| > Drop a marble from the top of the mast of a fast | > boat. It lands: | > i) behind the mast | > ii) in front of the mast | > iii) at the foot of the mast | >

| > Anybody have any other suchlike examples? | >

| | You mean more questions?.. | | If you open the fridge door does the room eventually end up hotter or | colder?

Hotter if still connected to the supply.

| | How do ice skates work?

They don't. Nothing is lifted against gravity.

| | Whats the other name for Dihydrogen Monoxide? | There are three; ice, steam and ...err... I forget the other one.

| Does the moon rotate? | Of course. It revolves around the Earth once a month and keeps the same face toward us.

| Do electrons flow from +ve to -ve or from -ve to +ve?

Inside the battery or outside?

| Why is very old window glass thicker at the bottom?

It has been conjectured that it is a viscous liquid. This is unproven, there are no large pieces of very old window glass. Nearly all very old window glass sits in lead in very old churches.

| Why does breathing Helium make your voice sound funny? | The velocity of sound in helium is different to the velocity of sound in air.

| How do you seperate a mixture of salt and sand?

Soak, filter, eveporata. I would have said 'evaporate' but you wanted a saparation.

| If electricity goes around a circuit and returns to the battery.. why | does the battery go flat? | | If a goat is tied to a fence post on the edge of a circular field..How | long must the rope be so that the goat can only eat half the grass? | Now you are getting serious.

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This one is not so simple as one might like to think, as I recall.

In 8th grade I received the incorrect explanation that it was due to the glass "flowing" under the influence of gravity. :-(

This also is a bit more different than most people think in that the *pitch* of your voice doesn't actually change with helium, but rather it's the

*resonances* in your voicebox that change.

Clever, I hadn't heard that one before!

---Joel

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