Old and the New

 Using the USB to 3 1/2 Floppy Disk. I haven't found a 5 1/4 equivalent yet, But I can use some very old PC's to still use them.

Potable Water

Making water safe to drink in the lab. Starting with River water and rainwater, we looked at how dirty they were. then put them through a water filter of gravel sand and activated charcoal. Clean but was it safe to drink - no. Next to see what bacteria is in tap, bottled distilled water and compare them to sea water, rainwater and river water.

 

Radioactivity

 Using the @Pascoscientific Wireless Geiger Counter with the sample holder and using different numbers of metal sheets to reduce the count.

Further Maths

 Playing with 3-D Vectors and comparing this to working with CAD. Rotating objects around, measuring distances to see real-life applications of the Maths.

Inside a plug

 Gone are the days when students learnt to wire a plug, but it is still helpful to look inside and look at a home wiring diagram to see that the sockets and lights are all in parallel.

World Population Growth

World Population Growth in Two Graphs. Over my lifetime is nearly a straight line and none of the students were bothered until we looked at the population size over the past 7000 years

 

Computer Storage

 Some computer history shows students the 5 1/4 Floppy disk, The 720K 31/2 floppy Disk, and the 1.44K 3 1/2 floppy disk onto the Single density CD to the DVD and Hard Disk. I also have a 1980s 300Mb Winchester exchangeable platter, giving the students something to consider.