Seth's Laboratory - Liquid layers / Testing Density

Its been one of those lazy sorts of weekends, Mrs M  was shattered when she got in from work on Friday night and we pretty much just vegged out. Not a lot has changed since then and Ive loved every minute of it, its been a lovely change. We have done a few little things, visiting Mrs M's sister and going to see her nan but apart from that its just been us playing with Opeie and keeping nice and warm in the house. We haven't even tidied the house much which really isn't like us. Its nice every now and again to have a weekend like this.

Seth hasn't been with us this weekend and as usual we really missed him and couldn't wait for him to get home this evening. We wanted to make the most of the time before he went to bed this evening so we set up a little science experiment to keep the boys entertained and get them thinking.

For this experiment we needed:

• A tall glass or Jar
• Water
• Cooking Oil
• Treacle
• Food colouring
• Selection of small items

  

Seth's and Opeie suited up and took a moment to go over the directions, safety procedures and where the exits where in case of emergency. Treacle is very dangerous don't you know!

Using three little pieces of tape we evenly sectioned off three spaces for the liquids to go so that it would be easy for the boys to know exactly how much they should pour in. First the water, followed by a few drops of food colouring (Seth chose blue but i think a red would have worked better as we were using black treacle).

After giving the mixture a little stir we added the cooking oil up to the next line. The boys were instantly hooked when they realised the liquids had separated and they couldn't wait to get the treacle in to see what was going to happen.

Next up the treacle, we had black treacle which i thought would have worked out better but we should have used light treacle as it turned the bottom of the jar into a bottomless abyss swallowing up everything we dropped in later in the experiment. The concoction looked great and the boys were really getting into the experiment.

The liquids were complete so then it was time to make use of the selection of small items. We had had a good rummage around the house looking for bits and bobs. I found lots of them in our messy draw (well we all have at least one).

 The boys couldn't wait to start dropping things into the mixture, these included Pasta, Lego (of course), coin, chalk, almond, nail, paper clip and a grape, Seth opted for a bogey but we swayed him away from that on, god knows what would have been next. Before dropping in each item we had a discussion about what we thought was going to happen and Seth came out with some interesting ideas and views.

One of our items was a chunk of lime, Seth's hypothesis was that if we dropped it in skin side down it would float at the top on the oil and if we dropped it skin side up it would sink down to the water, so we chopped the chunk in two and started our investigation. It was great how involved the boys were getting and i love hearing Seth's ideas. 

 The experiment took us about an hour with all of the discussions in between, Mrs M pointed out that we should have made all the things we we're dropping in roughly the same size to make it more accurate but it all went well and the boys really enjoyed it. the big discussion was whether the paper clip (that was coated in plastic) would have had a different outcome without the coating, but we'll save that for another day.

All our findings were documented and can be stored away for future experiments. I'm loving all the science that's going on in the house at the moment and Seth has been getting really excited at whats going to be next so stay tuned for our next visit to Seth's Laboratory.

So how does this work?

When liquids do not mix they will seperate and the most dense of them will be at the bottom of the container used. when you drop an object in to the mixture it will only sink until it has reached a liquid that is denser than they are. The size of a liquids molecules is what decides its density. The treacle has the largest molecules and they are packed together tight making it the most dense of the three. Water molecules are small but close together so it sits between the two and Oil is the least dense despite having large molecules as they are far apart.