Misc. Easy DIY Experiments: Home Science Without High-Tech

[Pengwuino]

Are there many experiments you can do that are like, 'famous' that you can do at home without spending hundreds or thousands of dollars for equipment? Mainly, I am thinken about experiments done say, a hundred years ago or more, that don't require high-tech stuff.

 

[whozum]

Archimedes buoyancy experiments :-)

 

[Pengwuino]

bleh, i don't like things dealing with water :D

 

[Mk]

Some guy a thousand years a go measured the speed of light with mirrors and wood and string, I think. How'd he do that?

 

[whozum]

He set up mirrors a couple km apart and had light shine through (forgot what theyre called) a huge wheel with slits in it, and by measuring the time between flashes of light he could calculate the SoL. I think he got pretty close.

 

[Pengwuino]

a THOUSAND?

 

[whozum]

http://en.wikipedia.org/wiki/Speed_of_light#Measurement_of_the_speed_of_light"

The first successful measurement of the speed of light using an earthbound apparatus was carried out by Hippolyte Fizeau in 1849. Fizeau's experiment was conceptually similar to those proposed by Beeckman and Galileo. A beam of light was directed at a mirror several thousand metres away. On the way from the source to the mirror, the beam passed through a rotating cog wheel. At a certain rate of rotation, the beam could pass through one gap on the way out and another on the way back. But at slightly higher or lower rates, the beam would strike a tooth and not pass through the wheel. Knowing the distance to the mirror, the number of teeth on the wheel, and the rate of rotation, the speed of light could be calculated. Fizeau reported the speed of light as 313,000 kilometres per second. Fizeau's method was later refined by Marie Alfred Cornu (1872) and Joseph Perrotin (1900).

Leon Foucault improved on Fizeau's method by replacing the cogwheel with a rotating mirror. Foucault's estimate, published in 1862, was 298,000 kilometres per second. Foucault's method was also used by Simon Newcomb and Albert A. Michelson. Michelson began his lengthy career by replicating and improving on Foucault's method.

In 1926, Michelson used rotating mirrors to measure the time it took light to make a round trip from Mount Wilson to Mount San Antonio in California. The precise measurements yielded a speed of 186,285 miles per second (299,796 kilometres per second).

 

[Danger]

Are there many experiments you can do that are like, 'famous' that you can do at home without spending hundreds or thousands of dollars for equipment? Mainly, I am thinken about experiments done say, a hundred years ago or more, that don't require high-tech stuff.

You could try duplicating the invention of the light bulb, trying out different filament materials and such-like. All you need for a simple vacuum pump is the compressor out of an old fridge. Just hook up to the inlet side instead of the outlet. Pickle or baby food jars can be used as bulbs, but I'm not sure what level of vacuum they can handle. The experiments can be done with battery power, so no serious risks involved.
There are tonnes of other things that can be done with scrap or very cheap parts. Galvanic response of frog legs, Hero's original steam engine, the photoelectric effect (not sure what the chemicals cost), original Babbage or Leibnitz difference engines (mechanical calculators), etc.

 

[Cyclotron Boy]

Other ideas

I'm quite fond of simple particle accelerators (linear accelerators, electrostatic accelerators, http://69.241.236.52/cyc2.html experiment is pretty easy to do, but sensitive. Best part about Millikan's experiment is that the apparatus is really easy to make.

 

[Pengwuino]

wow a DIY fusion reactor lol... is that at all safe?

 

[Pengwuino]

Oh man, anyone else know of any good experiments? Especially class-room type experiments... i think my old physics teacher would love to hear about some cool but doable experiments to do for class.

 

[ZapperZ]

This isn't a "famous" experiment, but I remember that this used to work "reasonably" well if one does this carefully. This also answers the question "How does one measure the wavelength of light using a pencil and a ruler?"

You need a pseudo monochromatic light source of course. So something like a cheap laser pointer or a good He-Ne source will do. You will need a metallic ruler - stainless steel if you can get it- that has very clear tick marks (preferably black). It must be shiny, that's important because you will use the reflection off the ruler.

Now aim the laser at the ruler and let the reflected beam hits a wall. You should have the distance from the ruler to the wall considerably larger than the spacing between the tick marks on the ruler. If the gods are with you, you should see something resembling an interference pattern on the wall. What you have done is make something similar to an interference from a diffraction grating (I'm assuming the spot size of your laser hits across more than 2 tick marks on the ruler).

You can then use the same mathematics as the diffraction grating interference experiment. The spacing between the tick marks is roughly the distance between the grating. Everything else is the same. You should be able to find the wavelength. If you know the frequency of the laser (this is usually given as part of the laser specs), you can even find/verify "c"!

Zz.

 

[Gokul43201]

Microwave mania

Warning : the above microwave "experiments" could be harmful to your microwave.

 

[The Reverend BigBoa]

Next time there's a thunderstorm in the area, you could try hooking up a key with a kite and then flying it. That should make for a hair raising experiment.

 

[Adrian Baker]

Oh man, anyone else know of any good experiments? Especially class-room type experiments... i think my old physics teacher would love to hear about some cool but doable experiments to do for class.

I'm a young (well 43!) Physics teacher and this week we have been doing Capacitors with the 6th form.

Experiment one is make your own capacitor with Aluminium foil and plastic sheet. Pull off about two foot (50cm) of foil and lay it on the desk. Put your plastic sheet on top, then another sheet of foil. Attach 5000V power supply to the two plates and slowly crank up the wick... You get great crackling noises and the two foil sheets pull together very tightly. The kids like this...
THEN, having discharged it carefully, see the effect of a thinner plastic sheet. Replace the original one with cling film (or bin bag-liner) and turn up the power...
At about 3-4000V the plastic breaks down and it discharges with a loud bang, blowing a small hole in the Aluminium with explosive force. Turn the lights off and turn the supply up to 5000V and you get a superb rapid-fire firecracker show with intense blue flashes and glowing vapourised aluminium blowing into the air. Ozone smell, sparks, noise, bangs... fantastic stuff!

The kids LOVE this one!

(Disclaimer - this is VERY dangerous, do NOT do it!)


I'll post experiment two later as I have to go now

 

[Pengwuino]

lol why did you guys do it then!

 

[whozum]

Nothing beats endangering the lives of students to show them the way things work.

A fun one we did was align a blowgun mounted at mouth-level aimed slightly below a magnet across the room at the same height. Attach a magnetic object, I think we used a small metal sphere to attach to the magnet, and have the switch to the magnet right next to you. Release the magnet right as you blow, and the two will hit it each sometime during their flight. Nifty little trick to show students that things really do fall at the same speed.

I challenged the teacher to do it with a quarter instead of a sphere, he nailed it too and I looked like a jackass for doubting him

 

[Adrian Baker]

Nothing beats endangering the lives of students to show them the way things work.

Absolutely right. Guess how many in the class didn't listen or couldn't be bothered... none! Also, capacitors ARE dangerous and sometimes a little knowledge is dangerous. They need to SEE what damage a capacitor can do. They are now keen to learn and suitably wary... which leads me to

Experiment 2
Get a suitable electrolytic capacitor and explain clearly why they MUST be connected the correct way round to the supply. Then, connect leads to capacitor, dangle it in a metal bin (with wooden board as a lid) and connect it the WRONG way to the supply. Turn up the power and stand back.
After a short period of time the thing explodes, blowing the board up a couple of inches and puffing smoke out everywhere. The loud BANG is awesome and can be clearly heard throughout the Department.

Next, do simple capacitor experiment and watch how carefully the pupils check polarity! They never forget that one either!

(Disclaimer - do NOT do this, it is dangerous)

NB, if you DO do this, use a low voltage capacitor (Rated at say 15V) and put at least this, but preferably more across it. You need a decent current too when it starts to break down. Only about 1 in 5 or so explode, the rest fizzle and smoke.
I did one in todays lesson and it was absolutely superb - it scared me it was that loud!

 

[Pengwuino]

Nothing beats endangering the lives of students to show them the way things work.

A fun one we did was align a blowgun mounted at mouth-level aimed slightly below a magnet across the room at the same height. Attach a magnetic object, I think we used a small metal sphere to attach to the magnet, and have the switch to the magnet right next to you. Release the magnet right as you blow, and the two will hit it each sometime during their flight. Nifty little trick to show students that things really do fall at the same speed.

I challenged the teacher to do it with a quarter instead of a sphere, he nailed it too and I looked like a jackass for doubting him

My high school physics B teacher did an experiment to show all things flal at the same rate but he used a paper plate or something and a grape with compressed air... evvvveryone thought we should aim lower but we kept missing until he pointed it right at teh objects and both were released they slammed into each other.