Monday, April 01, 2013
MiddleOne is an Even Number Old
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| Boy's room midway through painting | Boy's room after painting completed, note Ikea desk "Micke" which MiddleOne and I put together |
MiddleOne is an even number old. The sum of the first digit and last digit of his age is a prime number, the same prime number that you get when subtracting the first digit from the last digit of EldestOnes age (who is also an even number old). When you add this prime number to SMallestOnes age (who is an odd number old, and his age is the cube of a prime number), you recover MiddleOnes age.
This year MiddleOnes birthday fell on Easter Sunday. We promised MiddleOne for his birthday we would redo the space in the room he shares with SmallestOne to give him more personal space. This involved spending Easter spackfilling gaping holes in walls, sanding, washing, priming, painting, being slapped in the face by large slabs of ceiling paint that had been softened by the primers and fell off the ceiling, more painting, travelling to Ikea to purchase desk, lamps, chairs (Eldest One also scored a new chair and a lamp, we also resorted his room to give him more effective space), eating $1 Ikea hot dogs (mmmm), assembling said furniture and collapsing in a heap aching in muscles we didn't know we had.
In between we organised an Easter Egg Hunt and the Bettdeckererschnappender Weisle made MiddleOne a birthday cake.
Labels: home life, kids, miscellaneous
Friday, April 30, 2010
Let the Moon be Your Guide
So I gave a talk at the Bellevue Heights Junior Field Naturalists Club. I was giving a talk to a group of 6-9 year olds and their parents on astronomy on a night when the sky was so cloudy no hint of the full Moon. For Field Naturalists you would want to get them out in the field doing things: looking at the stars, finding south, measuring the Moon for the Moon illusion and that sort of thing.But with the the sky clouded out, how was i going to keep 30 or so active youngsters entertained for 45 minutes or so?
I had a theme "Let the Moon be Your Guide" and the main aim was to a) use something big and obvious to help find interesting objects and b) show that you don't need fancy equipment to see interesting in the skies. So I made some scripts in Celestia and Stellarium showing the Moon near interesting objects.
I also had some pictures of the Moon, a a big soccer ball (the Earth), a small soccer ball (the Moon), and a very big torch (the Sun) to demonstrate Moon phases. The kids were fantastic, they were enthusiastic and not afraid to talk about things. I had enthusiastic assistants to hold the Sun, Moon and Earth and demonstrate orbits and phases. I put up a picture of the Moon and had them find the Man, Lady and Rabbit (the also saw Crabs and Snails, and heck, they were right). I handed out star maps (but forgot to explain how to use them - blast!). The kids seemed to enjoy themselves, I certainly did (Thanks Rona for inviting me! and the kids for their infectious enthusiam).
As you know I'm a fan of using the freeware programs Celestia and Stellarium. I've put up the scripts for you to download and play with; download Moons.cel and put it in your Celestia folder, then use File | Open Script to run it. Download The Moon Guide and put it in scripts folder (unfortunately, it's version 0.9 script, I'll translate it to 1.03 later).
Labels: kids, Moon, science communicators
Sunday, December 06, 2009
Some Light Housekeeping
Over the years I have developed a vision for this blog, every week at least one "look up it's purty" post, one substantial post on soemthing of note, acouple of nice astrophotos and on Sundays a wildlife photo of the gad-zillions lurking on my hard drive or a guide to a neat family friendly bushwalk. I've managed the "look up" posts okay, but Sundays have been a bit of a flop.
So starting next Sunday, I'll be posting weekly instalments of MiddleOnes webcomic, Spleen Guy.
That should get the hits rolling in :-)
So starting next Sunday, I'll be posting weekly instalments of MiddleOnes webcomic, Spleen Guy.
That should get the hits rolling in :-)
Labels: home life, housekeeping, kids
Sunday, November 15, 2009
Eggshells in Vinegar (experiments with kids)
Left Panel, from left to right. Eggshells in water, white vinegar and a half eggshell in vinegar. Right Panel, eggshells in same order, five days later. End cup is eggshells in vinegar with pH indicator.
Inspired by Janet D. Stemwedel's Friday Sprog Blogging series on a number of experiments she's been doing with her kids, I tried a version of the Eggshell in Vinegar experiment Janet and her kids did (you have to scroll down, results here).
My assistant was SmallestOne. He and I used mostly crushed eggshells with one exception, half an egg shell. All were taken form hard boiled eggs. I included a control, with eggshells in deionized water, and the other three tumblers all had standard white vinegar in them, in one of the vinegar containing tumblers I added a Ph indicator - a dye that changes colour depending whether the solution is acid (as vinegar is) neutral (like plain water) or basic (like drano) to see if the amount of eggshells added exhausted all the acid in the vinegar.
Once added, the bubbles began to form rapidly around the eggshells in the vinegar solution, but not in the deionized water control. The bubbles were carbon dioxide form the acid attacking the calcium carbonate of the egg shell (how would you demonstrate that?). The bubbles were so vigorous they lifted the broken eggshells in a strong roiling action (see video). SmallestOne loved this, and the colour the Ph idicator went when we added it to the vinegar. He wanted to do more "colours".
Five days later we had a look again. The control deionized eggshell fragments were still hrad and crunchy, and surprisingly, so was the eggshell fragments in the tumbler with vinegar, maybe not as solid and crunchy as the controls, but, unlike Janet's, where her eggshells disappeared in only 24 hours, they were pretty solid! What happened? Three hypotheses:1) They have much stronger vinegar in the US.
2) The Eggshells were supported on the surface by a layer of carbon dioxide gas, and the vinegar was not as effective at getting to the shell.
3) I didn't use enough vinegar.
I suspect it's a combination of 2 and 3. Certainly the fragments were floating, and the glass with pH indicator changed colour, suggesting that the acid in the vinegar was, if not exhausted, certainly very depleted. However, the half shell egg shell, which had fluid inside and out, and was a lot more immersed on the solution than the fragments, certainly was greatly decalcified (see above image, where the previously hard eggshell is now like floppy rubber), except where it had bits sticking out of the vinegar where it had been bouyed up by the gas bubbles.
So now SmallestOne and I have to do a repeat experiment to find out which one of 2 and 3 is correct. What experiments should do you think we should do?
Labels: home life, kids, Science Blogging, science matters
Monday, December 08, 2008
Watching Mira Brighten - Record Your Observations.
The star Mira shines at roughly magnitude 4.2 in this image of the sky taken on 28 November 2008 (click to enlarge, otherwise the stars are a bit to dim to see).While most stars seem to shine with a constant brightness, there are some that undergo regular, dramatic change in brightness. Few of these are visible to the unaided eye, but two classics are Mira and Algol.
Algol is a bit hard for most of us in the southern hemisphere, but Mira is very easy, and Mira (omicron ceti), a star in the constellation of Cetus the whale, is a long period pulsating red giant and changes brightness from below naked eye visibility to a peak of round magnitude 2 (roughly as bright as gamma Crucis in the Southern Cross) in around 330 days. Mira will peak magnitude later this December, and will brighten visibly over this month.
The image above shows Mira on 28 November, when it was around magnitude 4.2, as of last night it was around magnitude 3.9. At the beginning of November I couldn't see it at all, so it was probably magnitude 5.0.Here's a activity for the next few weeks, record the changes in Mira's brightness. This will be difficult for the next few days, as the bright Moon will be nearly on you o f Mira, making the stars hard to see. However, after a few days you will be able to see the stars with reasonable ease.
But I don't know anything about magnitudes, you say. Estimating magnitudes is relatively easy, the image to the left is a chart of Cetus with Miras position marked, and the surrounding stars labelled with their magnitude. To estimate the magnitude of Mira, compare it to the surrounding stars. Is it brighter than a star labelled 3.5, and is it dimmer than a star labelled 3.0? then its magnitude is somewhere around 3.2-3.3.
Click on the chart to enlarge it and print it out. Use a torch with red cellophane wrapped around the business end to view it while star gazing (to keep your night vision), and wait for at least 5 minutes outside for your eyes to dark adapt. Cetus is just above the easily recognized Taurus above the northern horizon in the early evening. This would be an ideal activity for kids.
Labels: kids, Observational Astronomy, variable star
Click to read about or order
Click to read about or order
Click to read about or order
Click to read about or order
