2. BUBBLES Dr D Adriaens

3. What are bubbles?

4. How do we make bubbles? We need......to make a solution...to stretch the solution...and try not to pop it!

5. An experiment... (1) Let’s add together water (4 l), detergent (170 ml) and glycerol (15 ml). The detergent will DECREASE the surface tension of the water.

6. Heh? What is surface tension? Molecules attract. In all directions in a liquid But, different at the surface!

7. Oh....

8. An experiment... (2) And now, let’s blow bubbles!

9. An experiment... (2) And now, let’s blow bubbles!

10. An experiment... (2) And now, let’s blow bubbles!

11. So, where else are bubbles used?...

12. And? These bubbles are much smaller than the previous ones! Shall we make some more bubbles?

13. An experiment... (3) Now... How can we use it?...and I mean RIGHT NOW! WARNING: LIQUID NITROGEN is very cold (about -200°C!)

14. An experiment... (3) Risk assessment: N 2 : only teachers can handle this! (i.e. Do not touch!) Condensed milk, cream, flavouring, colouring, cones: edible – take care