Experiments

You will need some sea water.

Can you think of a way to measure the salinity of the sea water? There are many possibilities to figure out how much salt there is in sea water! How would you go do it?

When you fetch your sea water, take a little more than you need and put it in a bowl or glass somewhere where it can sit without being disturbed (maybe on top of a cupboard?). As water evaporates, what happens? Check occasionally on your glass with sea water, and look at how much water vanished since you last checked. What is happening in the glass? At what point can you notice salt crystals forming? How long does it take until all the water is gone?

You will need:

• Two glasses (or plastic cups)
• Food dye
• Salt
• Access to a freezer
• Ice cube tray

Mix the food dye and water, put it the ice cube tray, put the ice cube tray in the freezer and wait… Now you have colored ice cubes!

Fill the two glasses with tap water. Take one of the glasses and mix in salt until the water tastes like sea water. Then, put one ice cube in each of the glasses and watch what happens. Where does the ice melt fastest? And why?

For advanced oceanographers: you can also use “clear” (not dyed) ice cubes, then seeing what happens is a little more difficult (and a little more exciting :-))

You can read about what happens – and why – on my friend’s and former colleague Mirjam’s blog “Adventures in oceanography and teaching“.  There you can find many more exciting experiments, too!