Science group never came off yesterday due to various illnesses but we proceeded with some of the planned experiments anyway.
One of those days that illustrate that the simplest and oldest experiments are often the best.
Testing viscosity by dropping marbles (we used 4 of the same type) into glasses of liquid. We dropped all four at the same moment or as close as you can with human error. This made it hard to tell between the quickest 3 so we tested two at a time so we were able to compare and arrange them from highest to lowest viscosity. We had syrup, bubble bath, red wine vinegar and vegetable oil.
We then looked at comparing density and viscosity. We poured the least viscose into a glass and added them in order up to that with the highest viscosity. In each case we watched the more viscose sink to the bottom showing they had higher density. Looks pretty but fairly sure it would be horrible 😉
Final topic was surface tension. After various suggestions and discussions about why/how we get rain drops and puddles we moved on to the old favourite of milk and food colouring. Some people seem to have trouble with this. Not sure why or how, never failed me yet. Bowl of full fat milk, food colouring drizzled over the top. Touch the centre with a cotton bud soaked in washing up liquid and watch the colour rush away. Here is the science behind it.