The Leidenfrost Effect – revisited

Time to get back into the blogging game.

I made this video some time  back about an interesting phenomenon called The Leidenfrost Effect:

then came across the following from

thanks to 

Now that was cool


Teaching Heat in Junior Cert Science

There are a large amount of experiments in this chapter:

  1. Expansion and contraction of solids.
  2. Expansion and contraction of liquids.
  3. Expansion and contraction of gases.
  4. Water is a bad conductor.
  5. Expansion of water on freezing.
  6. Comparison of conduction in various metals.
  7. Convection in liquids.
  8. Convection in gas.
  9. Compare radiation in bright and dark surfaces.
  10. Plotting cooling curves.

This can lead to problems on two fronts:

  1. It can take an inordinate amount of time to get through the chapter.
  2. Students can easily get confused about which experiment goes with which concept.

It makes sense to group experiments into sections, and if possible carry out each set of experiments together.
This does however take a little organisation in advance.
So here we look at the expansion of solids, liquids and gases; the aim is for the students to get through all three in one period, although they would need to be prepared in advance.
Allow a double-class if trying this for the first time, for obvious reasons.
It’s never going to make the best of youtube, but hopefully it will help the teachers in my own science department. I hope to get through the rest soon, and then summarise as best I can on one page using diagrams.

Thanks to my second-year class of  for being amazingly patient.
And thanks to Millie for the brilliant camera-work (can you believe she had never used a camcorder before?!)

Colleagues: Please ensure that the equipment goes back into the correct boxes after.
Pretty please?
With a cherry on top??

Late update: I’ve just seen Tom Healy’s videos of the same expts on youtube, but put together much more lovingly. I reckon they all complement each other nicely!

New clips on youtube

I posted very few videos on youtube last year, and am determined to rectify that this year, and in particular to put up some clips of Junior Cert classes.

Here are a couple on spherical mirrors:

 The mirrors in this next one were purchased from educationalinnovations for about €20. They have a larger, 22 inch version for $1,195. Just a little out of our budget.

Microscale Vacuum Apparatus


This went down well at the ISTA conference in Letterkenny at the weekend where I was demonstrating as part of the Science on Stage team and I promised people I would let them know where I got it, so here it is:

There is a lot more where this came from. I posted a brief note on the site recently , so browse the entire site. Remember the dollar has rarely been this low.

I will stick a video of the kit in action on youtube sometime this weekend (hopefully).

Fun with soda cans

I did a series of demonstrations yesterday involving soda cans and stuck the video of it on youtube.

I wanted it to be just one video but it went well over ten minutes (15 to be precise) so I had to split it in two.
It was fun though.
One of the problems with this sort of thing is that students will either have seen everything before in lessons, or will probably have seen me prepare them, so sometimes they need a little encouragement when it comes to showing their appreciation 🙂

Today we did a fun class on microwaving anything we could get out hands on.
The simple lightbulb was by far the most impressive.
I’ll try it again after midterm and hopefully video it.