Wanted: Simple Science Experiments for Kids

Try this address. www.sciencetoymaker.org. It has some pretty cool stuff. We use it for home school projects. Let me know how your project works out.

Great site, my son has a arm project due in two days and this will help him/us get started.. Again, thanks

This has steam so careful ! Long sleeves, leather shoes, gloves, face shield, goggles, etc. Save an empty 2 liter plastic pop bottle. Put one tablespoon of water and microwave on it's side, no cap on it, until you see it boil for 10 seconds. Remove CAREFULLY, and put on cap CAREFULLY. Allow to cool and it will crush.

Lesson:

Steam displaces the air inside. Atomosperic pressure crushes the bottle. Air has density and weight and is witnessed as pressure pushing on the sides of the bottle.

*************

More simple >> No heat involved: Suck on the empty bottle and watch the sides collaspe / re-expand when you release suction. My kids were taught at 4 YO that milk sucked up a straw was really atmospheric pressure pushing on the surface of the milk in the glass forcing it up due to pressure differential. Could be why my kids are goofed up today !

I hooked a car battery to my moms big aluminum knitting needles and put them in a tank of water with some salt in it. One knitting needle got bigger and the other got smaller. A lot of gas boiled off. Hydrogen came off one needle, oxygen off the other. I made a poster to describe what chemical reactions were happening and occasionally lit off the hydrogen as I tipped the gas collector over to pour the gas out toward the roof of the building. The flame would run straight up to everyones surprise. It was fun and I've been electro-forming aluminum under water ever since. That was 50 years ago.

You can try triboluminiscence. Take a piece of sugar and crush it rapidly in pliers. It will make a tiny blue flash. You can also take the material that's called EverGlow. They make various security and warning signs of it - for example, the fire exit signs. It's very good. Put it under a lamp for a few hours and it will shine for another several hours. I made stars on my ceiling from this material and they really shine the whole night :-) And it's also highly triboluminiscent. If you cut it with scissors, it will give very strong green light - so strong that its visible even in a lighted room.

Wintergreen Life Savers work best.

jioiji

Hello,

This is not actually an experiment but it is an easy activity which I believe fosters an interest in engineering and technology and its not just for kids either.

Its called taking things apart and seeing how they work. Get the kids into a Taking Apart Club with a few simple tools and a notebook of course to record the process. Get them to figure out what the parts do. Get them to collect useful looking parts such as springs, gears even electronic components to see if they can make something new out of the bits. Get them to swap useful bits that they might need for their project. Get them to draw their project and the bits they collect

The local tip, (recycling centre) is a great place to pick up all sorts of stuff from cycles to printers and all sorts of interesting stuff for free usually. That would have to be a job for the supervisor of course.

The Engineer's Engineer

PS:I'm nearly seventy and I'm still doing it and have been for as long as I can remember and my grand children do it with me in my workshop.

This "Taking Things Apart Club" is a great ideal It also can teach kids to bag and label parts, record the dismantling, make sketches, etc. And then try to put the things back together!

There used to be a book of simple electrical experiments --with learning conclusions-- for kids called "Batteries And Bulbs". Don't know if it's still around (see the apostrophe, Rose?), but you might try the reference library or the children's section in the local public library. Maybe they have a catalogue selection under "experiments" as a subject heading.

Mark

ROFLMAO

I usually only get time to look at threads listed in the daily digest, but I was having a rummage today...and found this

Mark, that's a beautifully placed apostrophe! I'm proud of you .

Your tip lets you take things away!!! All the ones I know have banned this subversive off the cuff recycling.

Bah Humbug

My 7 year old son call's this activity "building a contraption". As a mechanical contractor I have lots of raw material for him to work with. It's amazing what a child can come up with. Recently he's been eyeing the welding machines.

How about rockets? It can be done with compressed air - e.g. from bicycle pumps & a valved supply. Kids build their "rockets" with fins etc, sit them on the launch tube, pressurise system, open valve and see how far they fly. Prizes for height & distance?

Friend of mine used this at the local high school - toilet roll/kitchen roll middles, cartridge paper needed to build rockets.

Sorry for recipe approach - time to get back to work!

Good Luck

PS I once took a truck wishbone, full LMS station with ADC and an impact hammer to one of these. The kids got to do their own modal analysis and watch the LMS model (which I built earlier) move around at the various modes. Engineering's not just about getting your hands dirty...LOL

Actually saw this in college physics class (more or less professor was trying to get kids awake) He took a front bicycle wheel and spindle (just as it would come out of the forks.) On one end of the spindle he had an eyebolt attached with several feet of string on it. Holding the spindle horizontal with one hand and giving the wheel a good spin with the other he was able to then hold the wheel by the string. The whole spindle and wheel were cantilevered with just angular momentum keeping the spindle horizontal. That looked really cool.

There's always the ramp and two disks race where the disks have the same mass, diameter and width, but have different radius of gyration. So one of them wins by a long shot. It's always good to trick them with this one right after dropping two 20oz soda bottles (one full of water and one empty) and taking bets which will hit the ground first. This would be a good time to show the video of an Apollo 17 astronaut dropping a hammer and a feather on the moon. I've seen the Apollo reel on NASA TV a couple times and they show the dropping of a hammer and a feather. In zero pressure they hit the ground at the same time. I was unable to find a clip of that; however, NASA has a strong education sector, I bet if you contacted them and asked where to find the video of that experiment to show at a science fair they would help you.

If it's a sunny day out side you can get a bunch of lenses and prisms and play with intense light beams. Just be careful, if they get carried away with the black paper it might range into your off limit domain. A kid burned a hole in the back of my black shirt in high school physics class.

You could play with electromagnets and make a telegraph. Have them help you wrap wire around a couple nails or iron bars and use a battery to supply the power. Do two sets and have the switch for electromagnet at one end of the room... you know the details probably. Print out a Morris Code cheat sheet and see how long that entertains them. I guess that might be getting out of the 5 minute range...

You could go the other way with magnetic fields and electricity, make a little light bulb glow by passing a magnet past a coil of wire. Perhaps cannibalize one of those "shake up" flash lights and show them the magic of how they work without batteries... Ties right in with taking things apart to learn about them.

I gotta get back to work...

Good luck, and have fun.

The NASA film must be available - we saw in school 20 odd years ago.

Variation on the bike wheel - twirly office chair and bike wheel as described...make sure you can get a hand's grip on both sides of the spindle.

Sit child in chair. Give child wheel, instruct to hold one hand on each end of the spindle. Tell child to tilt wheel from horizontal to vertical & back. Nothing happens. Set wheel spinning. Repeat tilt sequence...watch child & seat spin. Get child to vary rate of tilt, watch results.

Follow with 2 min explanation of conservation of angular momentum.

Prep needed: check school doesn't do this experiement! We did it in our A level Physics class (16 - 18 yo for non UK folks)

Check size of kids - you may need a smaller diameter wheel if they're tinytots

An all time favorite with kids is the glowing pickle. I use it to demonstrate conductivity of different materials. After going through the litany of boring conduct or no conduct exercises.....wood, plastic, coins etc...I rig the pickle. I use two metal forks and an A/C line cord. Connect one fork to one side of the cord the other to the other side. Wrap and tape wire and handle..Get a large dill pickle and insert the forks into opposite ends. Set the entire assembly on a non-conductive piece of wood. KEEP THE KIDS AT LEAST ARMS DISTANCE AWAY!!! Apply the 110V A/C and watch as the pickle starts to glow and crackle. It's more fun under dim lights.

"The Simplest Electric Motor in the World" - YouTube

http://www.youtube.com/watch?v=olR3-S296sc

Magnets are cool!!!

Wndrtch

The danger factor is serious, but you could try dicharging a couple farads worth of caps charged to line voltage via varistor and diode through various household items. Penny, empty pop can, matchbox car, the cat, hot dog, 110 volt light bulb. No not the cat.

(Need the varistor, because trying to charge a couple farads of caps to line voltage through a diode alone will trip breakers and reck your diode.)

You will want a cage of lexan (or something of the like) seperating you from your audience.

[edit] oh yeah, I don't know where you would go to find that many caps... roll your own?

A coworker of mine likes to make a battery with jars of lemon juice, and copper and zinc electrodes. It takes about 4 in series to light an LED. You can buy copper and zinc (anodized steel) parts where they sell plumbing stuff. Add the juice last after the cells are wired in series with the LED. (If it doesn't work at first, reverse the LED).

Guest recommends: "(If it doesn't work at first, reverse the LED)."

You can take advantage of this property of LEDs to convey additional information: Connect a second LED (preferably one of a different color) antiparallel to the first LED, then place a label under each LED to show the direction of current flow. (I might mention here that if you do use two different colors, each color will have a different forward voltage. Red LEDs exhibit the lowest forward voltage, whilst blue LEDs exhibit the highest. Red/Red, Red/Amber or Yellow, or Red/Green would be my first choices. Better yet, if you do use different colors, choose two colors whose forward voltages are nearly the same (Blue/White) and adjust the number of cells in your battery accordingly.

-e

JEgan, We at Co-engineering have one for you. It stumps a lot of smart people.

Problem: water gets into boat trailer wheel bearings.

Cure: Using a divers bell,a seal bypass,a compensator, all as per drawing; tell us why and how it works.

Also, give us the pressures at different depths of water in chronological order.

Tools required:

1/4 plastic tube & fittings, Manometer, oil, water and 3 oz. containers.

To see Drawing go to: www.co-engineering.net

Send Email address for animated drawing to del@co-engineering.net I will attach via return mail to you.

Del

If you have the vertical space somewhere, a Foucault's Pendulum is easy, cheap and quick. (set it going, and come back later to see how much the earth has moved in an hour.)

Heck, several pendulums of different lengths can be quite eye catching.

Slinkies trailed down the hall are good for showing sine waves.

Yusef1 wrote: "(set it going, and come back later to see how much the earth has moved in an hour.)"

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All of the Foucault Pendulums I've ever seen had a mechanism near the pivot to keep the pendulum going. These pendulums each had a massive weight at the end of an arm of at least ten meters' length. Even so, they apparently needed a little periodic kick to keep them going. On the scale of a kid's science experiment, I quite seriously doubt a scaled-down, unassisted version of one of these would swing with enough amplitude by the end of an hour's time to demonstrate much of anything.

Call me an experienced Doubting Thomas.

One year my daughter and I built a circa 1900 pendulum seismograph for her science fair project. I used two orthogonal knife edges, one riding on the other, with each edge riding in its own fused-quartz trough, as the pivot bearing. Moreover, the solid-brass pendulum bob itself weighed in at a little over twenty pounds. That represents a lot of momentum when you consider typical swing amplitude of a Foucault. Even so, the (undamped) pendulum was hardly moving after an hour's time. And did I mention losses due to air friction?

Your design I gotta see.

-e

Kids love hands-on science exhibits. Especially ones involving motion of some kind. I built a simple apparatus for my own kids - one they could control directly - in order to illustrate the principle of evaporation. Why do puddles evaporate faster on a hot day anyway?

The apparatus consisted of a surplus loudspeaker (8-12" will do) facing upward (that is, sitting on its magnet end) in the center of a shallow, medium-sized plastic tub. Attach the speaker to the tub by means of double-sided sticky tape so that it won't vibrate to one side. Connect the loudspeaker to an audio oscillator whose amplitude the kids can control by means of a large knob. (I built my oscillator using a 555 and a 1-watt amplifier chip, and set the frequency at the point where a clump of 30 metal BBs placed in the center of the speaker tend to resonate as a unit.)

Place 30-50 metal BBs in the center of the loudspeaker to represent water molecules. Metal BBs tend to gently clump together in the field of the speaker magnet, much as water molecules stick together in liquid water. And, like water molecules sticking together by means of their own electrostatic force, it takes a bit of energy to separate the BBs from the herd, so the analogy is pretty good.

Set the oscillator volume to zero - "cold" - before turning it on. Then gradually turn up the volume until some BBs begin to separate from the clump and bounce out of the speaker. The "water" is now "evaporating." As some BBs will roll under the speaker and stick to its magnet, it's not a bad idea to first wrap the perimeter of the speaker magnet with a thick strip of foam rubber or cloth so that the BBs can't get close enough to the magnet to stick. Then they can easily be recovered by means of a separate magnet.

As the child turns up the volume - i.e., the "temperature" - more and more BBs bounce out and, eventually, the "puddle" is dry. Repeat as necessary.

My kids played with this thing for hours (and probably know more about evaporation than most adults!)

-e

That's a cool idea.

Does it get very loud?

juba-jabba asked: "Does it get very loud?"

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Not particularly loud, but after awhile it got to be pretty annoying.

To adults.

As a precaution, I highly recommend treating yourself to a set of Bose noise-cancelling headphones and a new iPod nano. Stoke the 'Pod with Jimi Hendrix, Val Halen and The Matrix soundtrack, just to be on the safe side.

My original circuit could get much louder than was really necessary to demonstrate evaporation (although it might've been suitable to demo orbital mechanics :), so I inserted an attenuator resister in series with the "gain" (attenuator, actually) pot. Basically what I did was turn up the volume until the BBs got pretty frisky, but at a volume I could tolerate for a while. Then I powered down the circuit at that setting and measured the resistance of the pot. The amplifier chip had a fixed gain, and "gain" control was accomplished by means of attenuating the input signal using a voltage divider - the pot, in this case. Measuring the pot's resistance at the desired setting allowed me to determine a suitable value for the attenuator resistor.

My son was especially disappointed with this "upgrade," because at full volume the BBs used to bounce out at such speeds that they escaped the tub entirely - and that was cool!

If you're planning to build something like this, be sure to have plenty of BBs on hand - and out of reach of kids. Given half a chance, they'll completely fill the speaker with BBs just to see what happens when they crank up the volume and, underwhelmed by the result, they then try to scoop the BBs out of the speaker with their hands, tearing the cone. Hasta la vista, speaker.

-e

I am surprised that no one mentioned mentos and diet coke. Makes quite a fountain, and teaches about nucleation, solvation and expansion of gases etc. Lots of stuff on the web.

One thing I always thought was cool: attach two funnels at the wide end (tape is fine). Place this between two elevated sticks, fairly close at the bottom. wider at the top. The bifunnel thing will appear to roll uphill. Actually though. the center of gravity of the device goes lower as the bifunnel goes "up".

Tad

To demonstrate the basics behind the telephone, put a weak acid in a saucer and attach a metal strip to a wire. Put the metal strip in the acid solution and attach the other end to a loudspeaker. Connect the other contact of the speaker to a battery and the other battery terminal to a tuning fork. Strike the tuning fork to make it sound and dip the vibrating end of the fork slightly into the acid solution. The varying contact of the tuning fork arm with the acid solution will vary the current through the speaker and the tone will be heard. The weak acid solution can be made by putting a bit of battery acid into the saucerfull of water. The telephone uses a cartridge containing carbon granules that are compressed and uncompressed by audio waves hitting a diaphragm connected physically to the granules. When the granules are compressed, their resistance is lowered, passing more electrical current than when it is uncompressed.

Three simple experiments involving magnets:

1. Suspended Compass

Sandwich one end of a length of fishing line between two rare-earth magnets, and attach the other end to a ceiling light fixture so that when suspended, the magnets are an inch or two above the floor. Once released, the magnets will quickly oscillate about the direction of the Earth's local magnetic field.

To dampen the oscillations (the entire setup behaves like a torsion pendulum, after all), place a 6" x 6" x 1/16" plate of aluminum (or equivalent, so long as it's non-ferrous, and the size is only a guideline) directly under the magnets. The motion of the magnets will induce eddy currents in the plate that counter the oscillation and it quickly dampens out.

Speaking of eddy currents...

2. Magnetically-Dampened Pendulum

Using this same setup, pull the magnets to one side and let them freely swing back and forth, like a pendulum. Then place the plate on the floor under the magnets and watch what happens. As the magnets swing over the plate, their rapid motion induces large eddy currents which counter the motion. What is interesting is that the motion is not opposed along the swing path, but at a continuously-varying angle to it. This causes the magnets to change course in a chaotic way as they pass over the plate. Yet, when the magnets are stationary, no currents are induced and the plate has no effect on the magnets, underscoring the point that only moving/changing magnetic fields induce currents in conductors. It is vitally important to this demonstration that the plate be non-ferrous, as an iron or steel plate will attract the magnets and swamp the effect.

3. Magnetic Grand Prix

Take a sheet of aluminum, say, one about 12" wide x 36" long x 1/16" (or more) thick, and lean it up against something so that the sheet slopes at a 45° angle, more or less. Find or make a piece of non-magnetic metal or some other material having roughly the same size and weight - and surface finish - as one of the rare-earth magnets. If necessary, you can sand the object to obtain the required finish, then paint both the object and the magnet to ensure that their surface finishes are comparable.

Then, "race" the magnet against the object by placing both at the top of the slope and releasing them. The magnet will lose every time, as it induces currents in the sheet that oppose its motion. The stronger the magnet, the slower it will creep down the slope. The other object, of course, will quickly slide to the bottom unopposed and win the race.

Alternatively, find two toy cars which freely roll on a hard surface. Attach the magnet to the underside of one car and the object to the underside of the other. Then race the cars in the same manner as above. Again, the "magnetic" car will lose every time. By using cars you eliminate the requirement to have comparable surface finishes, and you can add weights to the non-magnetic car to get equivalent net weights.

Provided the magnet surface finishes and weights are nearly the same - or if you use toy cars - you can also use this technique to find out which of several magnets are the strongest. If the magnets differ in weight, add non-magnetic weights to the smaller magnet's car to bring its weight up to par with that of the other car.

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Where to find rare-earth magnets? Edmund Scientific is one (albeit very expensive) source. Or, if you can find a source of free (and possibly broken) or cheap computer hard drives (5 1/4" drives are best), you can take one apart to get the magnets out of the read/write head arm motor. These magnets are ideal, as they are flat, very powerful, and fairly large as rare-earth magnets go.

A good source of small copper sheet is your local hobby store. In my neck of the woods, Hobby Lobby has rigid sheets of copper and aluminum. Use copper if you can get it. Next to silver, copper is one of the best electrical conductors around. Your local metals supply company would be a source of larger aluminum sheet for your Grand Prix "racetrack."

-e

The version I saw slid two identical magnets down two tubes of nearly equal geometry, each magnet had a tube. One tube was aluminum, the other was plastic. They were painted to look the same. The magnet took an unreal amount of time to "free fall" through the vertical aluminum tube; where as the one in the plastic tube just plummeted to the floor.

Hi juba-jabba. This, too, is a very cool experiment, as the magnet falling through the aluminum tube appears to "defy" gravity to some extent. A drawback to using tubes is that one cannot see the magnets fall except by looking into one end of the tube. This makes it difficult for science-fair visitors to see the action. On the other hand, the magnets plop out of the tubes at different times.

I might also mention here that two good sources (in the U.S., at least) of aluminum sheet and extruded aluminum tubing are Home Depot and Lowes stores. For plastic tubing, PVC pipe is a good candidate, also available at these stores.

-e

I should also mention that copper pipe is available at Home Depot and at Lowes, is cheaper than extruded aluminum pipe, is a better conductor than aluminum (accentuating the effects of induced currents), and comes in diameters comparable to smaller-diameter PVC pipe.

-e

Speaking of compasses (#1, above), you can determine the polarity of the magnets by using a hand-held magnetic compass. What may be a bit confusing to some is that Earth's Magnetic North is actually a magnetic south pole. The North-pointing end of the compass needle is itself a magnetic north pole, so it will point to the south pole of the magnets.

Caution: Be careful not to hold the compass too close to the magnets, to avoid damaging the compass. Rare-earth magnets are powerful little beasts, and they can also pinch little fingers in the way of two magnets snapping together.

-e

http://members.aol.com/SciRealm/KidScience.html
a link with some science experiments i remember doing as a kid i think in middle school

You may have done this or seen this before, but have you try putting a hard broil egg inside a bottle without cracking the egg?? First start by showing the size of the egg is bigger than the opening of the bottle, then light a match and drop it inside the bottle and cover the opening with the egg. Now watch the egg as the match displace the air inside the bottle, and the egg will be pushed inside by the atmospheric pressure. It's kind of cool for elementary school kid to see, I think.

MidniteFighter

I've seen this done with a peeled hard-boiled egg. Your post's wording - "without cracking the egg" - suggests doing this experiment with the shell intact. Is this your intent?

-e

Yes, but keep in mind that due to gravity, the egg shell may be "crack" when it hit bottom. (The law of natural still apply. :-) )

MidniteFighter

Home-Grown, Pencil & Paper Photocell (Photoresistor)

Here's a simple experiment where a kid can make a working photocell (photoresistor) using a soft pencil and a piece of paper. To see the photocell work you'll also need a digital multimeter, such as can be found at Radio Shack.

To make the photocell, all you need to do is to draw a series of interdigitated bars on a piece of paper, as shown in the figure below:

Then, using a fingertip or cotton ball, lightly smudge the pattern to somewhat darken the gap between the lines, so that the end result looks like this:

Now, place the multimeter in the Ohms or Resistance setting connect one lead to the left edge of the pattern and the other to the right edge. Alligator clips that fit snugly over the ends of the test probes are ideal. To keep from puncturing the paper with the alligator clips, fold a strip of aluminum foil over each edge after backing the paper with a piece of cardboard (the cardboard backs of notepads are best - or you can draw the pattern directly on the notepad backing). The foil provides a better contact across the entire length of each edge, whereas without it, the alligator clip contacts the paper at only a few - and maybe not enough - points.

Once everything's hooked up, measure the resistance of the photocell in the dark (using a dim light to see the multimeter, of course), and again under lighted conditions. Varying the light intensity should result in variations in the measured resistance.

If you don't see much variation, try smudging the pattern a bit more. The carbon (graphite) in a pencil "lead" is a photoconductor.

I discovered this property for myself quite accidentally in 6th grade while measuring the electrical resistance of various lengths of pencil lines drawn on paper. One of those Eureka! moments - but I kept my clothes on that time.

-e

I might add here that in you're electronically inclined, you can use the photocell in conjunction with the BB/speaker setup I described earlier to vary the amplitude of the oscillator in proportion to the intensity of the light falling on the photocell. (Brighter sunlight => faster evaporation) To do this you can use an operational transconductance amplifier or one of the various variable-gain amplifier chips on the market (Analog Devices 600/602 VGAs were good; their successors are better) to function as the gain element in the circuit in place of the potentiometer. Some experimentation is required, as the nominal resistance of the photocell is a function of one's artistic abilities.

-e

Very simple, very easy, very puzzling!

You will need:

-Qty(2) 250mL Beaker

-Qty(1) 500mL Beaker

-A container with capacity > 500mL

-Water

-Rubbing Alcohol

Procedure:

-Fill one 250mL Beaker with H₂O and the other will the Alcohol

-Dump them both into the container and shake (or stir) for a few moments

-Pour the contents of the container into the 500mL Beaker

Result:

The volume of the mixture will not equal 500mL! The water and alcohol molecules combine analogously to a tub of basketballs mixed with baseballs. My kid did this experiment for an elementary school science project on molecules... It was received as "Magic" by his fellow classmates.

Enjoy!

So that's what's going on! For a moment I thought they'd jipped me (by volume) when I ordered that rum & coke at the party last night...

-e

I vaguely recall my sons science teacher asking the kids to think of experiments to do at home years ago. One of the ideas I found from a book was making 'rubber' - warm some milk in a pan and add vinegar whilst stirring.A load of really 'gloopy' stuff forms which you can scoop out , squeeze (to get rid of milk residue) and you are left with a handful of very rubbery substance. The proportions were of the order 1 pint milk:1 tablespoon vinegar (the milk only has to be hand hot ). You'd have to test this yourself first , and I'd recommend hand washing/disposal of 'rubber' after the fun (due to milk use + hygiene ) , but I was amazed when I tried It .Perhaps more importantly I don't recall the chemistry - who cares it's fun science !

A 2-stage rocket is also possible with your soda bottles and a couple of balloons. It's tricky to describe - cut the base off the bottle , inflate 1st balloon inside bottle and grip the balloons neck . Insert second balloon and inflate so it squashes the neck of balloon 1. I haven't tried this , but it looks viable from the drawing I saw.

Kris

Hello; I think you will find that there are two types of information you recieve from us science/engineering folk. The first is from the people that like to gloat and the second is from people that care. I will not put down anyone as a good pat on the back doesn't hurt anyone. Having said that, please rethink 'Science Experiment'. As a person that has raised and taught, not to say others haven't, it is very easy to fall in the well of previously done 'stuff', volcano et al. Solution. Safety first! Even though the experiment is docile, get into the habit of forcing to wear safety glasses and ask them why? Keep doing it. It makes them feel more scientificly minded. Lab coats if budget permits are good also. ( PS: If $ doesn't allow it, call up the nearest scientific lab and plead your cause, you will get them for free. If you have any problems, I'll do it for you. Most important to them is to be involved so thay show good face! Second: Don't teach them what will happen; let them find out and write it down and ask why. Then tell them. Third: Some good original experiments.... Simple things like: 1. How much does a bird cage weigh when the bird is on its perch vs. flying? 2. What is sunlight made of? Give them a prism and show them. 3.Does something get heavier or lighter when burns. ( Yeh I know fire is out but Mg makes one heck of a good example ). 4 How many marbles can you support in a boat made of a 4" x 4" piece of foil. 5, Can you make a boat sink by introducing a gas like a bubble stone from an aquarium? Why? 6. Best yet, and this will teach them about the lies they see and here on TV. A vacuum pulling a car. Teach or show them that the ability of a vacuum is not what power it is, it is only its ability to pump away the leaks faster than the 14psi ambient atm. P. is. Example. Take a 1"x1" plate and lift anything heavier than 14 lbs. it will fail. Take the same vacuum and attach a 10" x10" plate and lift then, it will pick up 1400 lbs. Sorry for over explaining, but this is exactly the course I offer on the road anywhere. Ashman.

an interesting experiment as below:

a green pingpong ball below a filer will drop down, but when you blow air from top, look, what happen? the ball dont drop again.