What's new here?

Archive for the ‘Solar’ Category

So you want to view the Eclipse…

On August 21st, 2017 a large portion of the Continental US will experience a total solar eclipse. Much of the rest of the continental US will experience at at least a partial eclipse: Philadelphia will have about 78% totality, NYC 75%, Washington DC 84%, Chicacgo 88%, Los Angeles 70%, Seattle 93%, etc.


Solar Power – Active vs. Passive

Solar power is one of the great potential sources of energy we hope will replace FUninthesun polluting fossil fuels over the coming years. Specturm Scientifics has sold many teaching toys that use solar energy to demonstrate different effects, But did you know there were technically two types of Solar Energy generation? They are called active and passive solar energy and how they work is very different, despite coming from the same energy source (of course, pretty much everything has the sun as an energy source when you dig deep enough). Let’s discuss passive solar energy and the items we have that demonstrate it first:


If you’ve ever walked barefoot on a black asphalt street on a very hot, sunny day you are experiencing Passive Solar power in action. You might be fine on the brighter colored concrete sidewalk, but the black asphalt absorbs heat much better and can get uncomfortable to walk on barefoot. This is a very rudimentary demonstration of the sun’s power.

Another example is when you use a magnifying glass to concentrate light to start a campfire. Here the surface area of the magnifying glass is all concentrated into a single point that can get quite hot.

So how do we use this kind of solar power to make power that we can use? Well the present technique is Conctrated Solar Power. With this a large fields of parabolic or other curved mirrors are set up to track the sun and conctrate as much of the light as possible. The light is concntrated at some central point where a thermochemical reactionPS10_solar_power_tower  or heat engine is placed to convert the solar energy into electrcity.

While we lack the ability to ‘scale this down’ to a toy level, there are more than a few solar demonstration items that can be used to show the power of passive solar energy. The first being called (surprise) Solar Science


With this kit students will heat water using a passive solar heating system as well as as construct a miniature solar oven where they can cook and egg!

OK, so what if you want to step this up a bit? Well there is the Sun Spot Solar Oven



The Sun Spot is a much larger version of the solar oven you build in the Solar Science kit. Large reflective panels concentrate light at a wired point. Objects can be placed there (such as a hot dog). Temperatures at that point can easilt reach 350 degrees F.

Active Solar Energy

Active solar energy generation is probably more familiar to most of us, especially as solar panels become more ubiquitous. We use them to charge our smartphones, they power garbage compactors right outside our store.

2015-08-25 13.51.54

Active solar power uses photvoltaic cells to convert sunlight into electricity. While this does have the advantage of direct electricity generation (no thermochenical or heat engines are needed at a focal point) they do have a problem with efficiency.  The solar cells you can see on this trash compactor will each generate about 0.5V and 2W in direct sunlight, with 18 cells in total, you have about 9V and  36W. Presumably the power generated goes to a battery that can operate the compactor motor when it has sufficient power.

As for active solar items we have, where do we begin?

Solar Owl?


Solar Science Kit?


Solar Powered Rainbow Maker?


Solar Mechanics Kit?


So many Solar choices!

Want to buy Solar Science Toys?



So your Radiometer stopped working…

Radiometers, or as people who come into our store describe it: “That thing that spins in a bulb in sunlight” are a great little demonstration of solar energy.

569There’s no assembly required, just remove the Radiometer from the box and put it under light. The vanes should start spinning right away.

But every now and then the Radiometer may stop working. You can put it in the brightest lights and yet nothing happens. What to do?

Well repairs to a stopped Radiometer are almost painfully simple, and yet sometimes they need to be explained carefully. This is especially true since Radiometers are made with thin glass and can be easily damaged.

First Repair: Two finger tap

Most of the time the reason a Radiometer stops working is because the vanes have come dislodged from the needle-like post. The vanes are supported from the post by an upturned cup of glass with a pointed bottom. To operate the needle point must fit in that bottom perfectly. This is not always as easy as it sounds as the vane’s momentum can cause the cup to slip off the needle. To get it working again you will need to reset the cup onto the needle with a tiny bit of external force.

2014-11-25 13.49.51Give your Radiometer a gently but firm tap with two fingers directly on the very top of the bulb. Do not tap too hard as the bulb is made of thin glass.  If the cup has simply dislodged itself from the needle this gentle impact may cause it to reset itself. It is also possible that the vanes have gotten a little stuck from one reason or another and this impact can loosen them.

Second Repair: Upside Down time.

If tapping does not fix the problem it is time for the ‘full resetting’ of the cup on the pin.


2014-11-25 13.50.03Take the Radiometer and turn it directly upside-down. Then quickly flip it so it is right-side up again. When you invert the Radiometer the cup will come completely off the needle and when you revert it the cup should reset exactly on top of the needle. Place it back into the sun and see if this reseting worked. If it did not, try it again.

Still not Working? Troubleshooting tips:

So after trying these your Radiometer is still not working? Try these helpful hints to see if there is another issue:

1) Not enough light. Some Radiometers may operate by a glimpse of moonlight but most aren’t that sensitive. Try putting the Radiometer in direct sunlight or very close to a lamp and see if it works. Sometimes Radiometers just can’t get enough energy from a cloudy day! Keep in mind that the sensitivity is unmeasurable and there can be great variations of sensitivity even within a brand of Radiometer.

2) Unlevel surface. If there is anything under the base of the Radiometer, remove it and see if that helps. A Radiometer won’t work if it is tilted for any reason so check the shelf or windowsill you place it on is reasonably level. If not, try another sunny location.

3) It’s cold outside. If your windowsill is very drafty the Radiometer may have problems. See if you can find a warmer location.

4) It just won’t work! While not all Radiometers are created equal, it is very, very rare that one simply won’t operate. But it does happen. To make certain either place the Radiometer in direct bright sunlight or mere inches from a lamp bulb. If it won’t work even under those conditions (after you follow the tap and flip repairs above) it is likely a non-operating radiometer. Time to replace it.

Want to buy a Radiometer?


Classic Spectrum Blog Repost: Projection Solar Astronomy

Editorial Note:  With a partial solar eclipse being visible in select parts of North America today it is a good time to re-cap one of our older posts about how to project and image of the sun onto cardboard using a telescope or binoculars. Sadly given that we are still in a Nor’Easter here in the Philadelphia region we will probably not be able to enjoy the eclipse.  So be sure to view it for us if you are able:


With the just passed annular eclipse out in the Western part of the USA a couple of weekends ago and the upcoming transition of Venus you might be inclined to buy  a fancy solar filter for that telescope.

Well there might be a problem with that. See everyone else had the same idea as you, and that means the manufacturers of such filters are pretty much out of stock! It can even be hard to find just the filter material! What to do?

Well, there is another way of viewing the sun without the use of a filter. It can be tricky and it can be dangerous if proper care is not taken.  That method is called projection astronomy. This is where you use the telescope & eyepiece to actually project the image you would normally see with your eye onto a board or other bright surface.

What do you need? You need a telescope with an eyepiece (preferably lower-medium powered), a sunny day, and something to project the image onto.

We came up with this kind of last minute, so we just used a flat box on a clipboard. It had problems with the box seams, but the surface was very bright (brighter than the average piece of printer paper) and so would give a decent image.

Crude, but effective.

Next up, we need a telescope. We used an Orion StarBlast 6 , mostly because that is what we had around the store.

Telescope is in action.

Note that the picture above shows the telescope in action. When setting it up and aiming it you should LEAVE THE DUST COVER ON.  This is the best thing for your safety.

Aiming your telescope at the sun is pretty easy, just try to get your tube to make the smallest shadow possible.  When you think you are on target, remove the dust cover and see if there is any light coming through the eyepiece. DO NOT look into the eyepiece, ALSO DO NOT LOOK DOWN THE AT THE EYEPIECE. View it from the side. We are not responsible for your losing your eyesight!!!

Now a further  safety warning: Try to avoid getting any body parts in the path of the light coming out of the eyepiece. Hold the board on the edge, work around the telescope, not over it, etc.

So now that you are lined up with the sun, you can see what kind of image you have. Place the projection board about a foot or so away from the eyepiece. Move it closer or further away to try and get it into focus. DO NOT bring it closer than 6 inches from the eyepiece, the light is a little too concentrated there and some types of paper might burn.

Some adjusting will be needed. It is best to move the screen rather than the telescope. If you must adjust the focuser, put the dust cover over the front of the telescope.

So what kind of view so you get? Well, here is a shot of the screen that is a little closer than the last photo:

This didn’t show up too well in the photo, but if you look closely, you can see some sunspots projected on to the board to the right and right/down of the center.


How well will projection astronomy work on the transit of Venus? We don’t know for certain. The sun will be very low in the sky and there may be more distortion or discoloration as a result. But if you have the time and the telescope, this isn’t exactly an expensive experiment! Just remember to be careful! Pointing a telescope at the sun always has risks – just use common sense and keep out of the path of the projected sunlight and you should  be fine!



Friday Means Dancing Penguin Chorus Line

Yeah. I’m being lazy. Don’t care. DANCING PENGUIN CHORUS LINE!

(You really want a Dancing Penguin!)


All our fun window Solar Science Toys – With Video!

Almost a 1-1/2 years ago we added a nifty little product to out line. It was a frolicking solar powered flower. We liked t so much we even did a little blog post on it:


Naturally, we also made a video:

Since we added this flower, there have been many other fun solar products added to our solar line. First of all we have added a mini-Solar powered frolicking flower. This model version comes in the flower and pig/elephant designs.


Naturally, we have a video:

The next model, which got so popular it is out of stock until May, 2013 is the Solar Powered Hoot Owl.


Oh look! A video!

Finally, there is our most recent addition, and perhaps the cutest solar powered toy of them all: Our Solar Powered Dancing Penguin!


Of course, a video must be seen of this cute penguin in action!

Want to buy Solar Powered Toys?

Interested in more serious solar powered educational items?




More MOVA Solar Powered Spinning Globes – The Rest of the Planets

We’ve already discussed the MOVA Solar Powered Spinning Globes in a previous entry, and covered the Blue Earth, Jupiter, and Moon versions of the globe. Now  we present the models that make much of the rest of the solar system. Let’s start with Mars:


The Red Planet shows excellent detail of valleys, craters, extinct volcanoes, and other incredible features of Mars’ surface.  As with other MOVA  models the globe gently spins with just a little bit of light -despite not showing any solar panels, batteries, or cords.  It will spin on or off the included base.

Next up is Venus


Venus shows the superheated and volatile nature of Earth’s sister planet. The surface is shown in red colored detail with the high albedo atmosphere stripped away.

Moving to the outer planets, we have a solar powered spinning globe of the ringed Gas Giant Saturn. Sadly, they were unable to make a ring on this model of Saturn. So instead the spinning striated surface is shown.


The final planet in this series of MOVA Solar Spinning Planets is Neptune. Neptune is a wee bit minimalistic but it does have some details that will show when it spins.


There are no plans for MOVA globes of Neptune and Mercury at this time, as far as we know.

The final piece in the astronomy series of MOVA globes (there will be more globes in the near future, but mostly Earth globes) is the spinning Constellations Globe.


Like any decent astronomy globe, the constellations are shown in their proper position in the night sky. An image of the Milky Way is shown on the model as well!

As always, the MOVA Solar Spinning Globes require no batteries or cords, and they all have FREE SHIPPING within the continental US.  Customers in HI, AK and PR should contact us for shipping costs.

Want to buy more Astronomy Items?