Tuesday, 19 June 2012

how old?

Me: Guess how old I will be tomorrow? Matthew: Umm, 20? Me: Older. Matthew: 26? Me: Older. Matthew: 27? Me: Older. Matthew: 28? Me: Older. Matthew: 69? Me: Younger! Matthew: Sixty-Zero? Me: Younger. Matthew: Hmmmm... 41? Me: Younger. Matthew: Oh, I know, I know, thirty-ten! Me: Thirty-ten is forty, and I'll be younger than forty. Matthew: [thinking hard] 31? Me: Older than 31 and younger than 41.... We went on and he eventually guessed correctly. But that's all you need to know. Older than 31 and younger than 41. Praise God, I'm still in his hands.

Wednesday, 6 June 2012

what we learnt today

Eclipse viewers that were designed to view an eclipse of the sun by the moon will not allow you to view a transit of Venus. The image of the sun is simply too small to be able to see the infinitesimally smaller image of Venus.

But, not to be daunted, we improvised.

First we made a big pin-hole viewer. The longer the distance between the pinhole and the screen on which the image is viewed, the larger the image will be. So we used the coffee table. We taped cardboard to one end, with a pinhole in the middle. We covered it with blankets so as to block out the light. We mounted a white piece of paper at the other end for a screen.

To view, simply stick your head inside!

This worked. The image was just big enough to see the tiny, tiny speck that was Venus.
But what worked much better was this.

Glen rigged up a small set of binoculars so that the image of the sun was projected onto a piece of paper on the ground. The image was large enough to view the transit.

Here are the best of the photos we managed.




So now you all know what to do for next time. 2117.

Tuesday, 5 June 2012

how we made a pinhole viewer

Here are some easy to follow photos showing how we made a pin-hole viewer, as mentioned here.

We followed (and slightly modified) the method from here.

What you need:
  1. a cereal box
  2. scissors
  3. baking paper
  4. masking tape or packing tape
  5. thumb tack (drawing pin)
  6. aluminium foil
  7. black T-shirt

What you do:
  1. Cut a flap in the bottom half of a cereal box as shown in the picture below.

  2. Cut a strip of baking paper the same size as the base of the box and tape it on the inside of the box, about 5cm from the base.

  3. Use the drawing pin to make a hole in the middle of the base of the box.

  4. Tape up the flap.

    We found that just masking tape wasn't enough to block out the light so we cut strips of aluminium foil or cardboard to go over the edges before covering those with masking tape again.

  5. Cut off the flaps at the top of the box and cut a curve in the edge. This is the viewing end and will be held over your eyes.

  6. Have a good look around outside on a sunny day! Everything is up-side down!

  7. Here comes our modification.  Tape the bottom of a black T-shirt around the viewing end of the box. We went over the masking tape with packing tape as it is stronger.

  8. Push your head through the head-hole of the T-shirt so it is on the inside of the T-shirt.

  9. Hold the viewing box up to your eyes as before.

  10. Have an even better look around outside on a sunny day! You can even see everything in colour.

As you can tell, I was pretty excited by this project. So easy to make and it worked so well.

Hoping for a sunny day tomorrow for the "Transit of Venus"!

QUICK! It's not to late to make a pinhole viewer!

Tomorrow there will be an eclipse of the sun by Venus. Actually it's not really an eclipse but a "transit".  Venus is not big enough or close enough to eclipse the sun, but it appears to move (or transit) across the face of the sun.  Only you can't see it with your naked eyes because you have to look directly at the sun AND THIS IS VERY DANGEROUS.  So here's how to view the transit.

Make a pinhole viewer.  They are easy and take about half and hour and use materials you have about the house.

Here's an easy one that is specially an eclipse viewer.  Our nine-year old made it on her own.

Here's one that is a general pinhole viewer.  This you can use for viewing everything through the pin-hole and everything is UP-SIDE DOWN.  I kid you not. It is amazing.  It has easy instructions to follow as well as an explanation of how it works.

You really need to block out the light.  When we taped the boxes, we put strips of foil along the cut edges first and then covered those with masking tape.  This kept out the light much better than the masking tape alone.

Then we made a really great improvement to the pin-hole viewer.  We took a black T-shirt and taped (using strong packing tape) the bottom of the shirt around the viewing end of the box.   Then you put your head through the head-hole to the inside of the T-shirt.  Thus all the light is blocked out and you get a really good picture on the inside.

We are really looking forward to the eclipse.  Let's pray for a sunny day!

Check out this site to find out when you can "see" the eclipse. Those on the east coast of Australia should be able to view the whole transit (should it be a sunny day).