Monday, March 18, 2013

Monday science-fest

I spent some time on the weekend while I was fighting some cooties and feeling achey and lethargic scouring our science books to plan what science we would do this week. Two books I really love are

I gathered supplies - lots of them

The first one we tried was 'Ice Cloud' from Science Rocks. We haven't observed the results yet so I'll wait and add that one tomorrow.

Our next one was from the same book called 'liquid layers' . We poured water dyed with food colouring, oil and molasses into a glass and dropped in small objects of varying weights, gave it a good stir to mix the liquids and set it aside for the suggested 30 minutes. Tick tock, tick tock. Thirty minutes later our liquids were still mixed and had not separated by density as they should have.  The oil had separated but the molasses and water still seemed a bit confused and it was hard to see if all the objects were on the bottom or somewhere in the darkness of the water/molasses mixture. We got on with our next experiments and then the day got busy and we haven't looked at them again but will tomorrow.

'Crystal Creations' also from Science rocks was next. We filled jars with hot water, almost to the top and added 1 tablespoon of powdered alum to each jar and stirred. Next we each took a paper clip and pulled it open to form a kind of S shape. Using cut up pipe cleaners we made snow flakes by twisting the pieces around one another. Then we hooked one end of the paperclip over a pencil and hooked the other end onto our snow flakes. By resting the pencil across the top of the jar the snowflake was able to be suspended without touching the sides (this will spoil the results) and allowed it to be submerged in the water. Tomorrow we should see crystals formed on the pipe cleaners, if only diamonds were so easy and fast to create!!! The alum we had is from I don't even know what maybe a play dough recipe or something from forever ago - I'm not sure if its age will affect the outcome.

Our final experiment was to discover how dense objects are (once again from Science Rocks). the concept was a little over T2's head but she enjoyed it all the same. T1 fully understood it.

First we needed a 2 litre plastic pop bottle. I had asked G when he went to the store to buy any kind of pop as long as it was 2ltr. It was some awful cheap stuff that we poured away after a quick taste to confirm that it was nasty stuff! The bottle was perfect - it's cheapness made it easier to work with than I think a popular brand of pop would come in.

We had to cut the top half of the bottle off and we tossed that in the recycling. Then we made a hole (the bottle was flimsy enough that I used a paper hole punch) maybe an inch from the top of that section. Then we secured half a drinking straw in that hole with modelling clay to seal the hole (actually we used that tacky stuff to stick posters to walls because thats all we had. It worked fine).
 Next we needed some household objects that were small enough to fit in the bottle half. We chose rocks, toys, kitchen supplies.

Next you need to fill the bottle half with water, with a container under the straw. Keep filling until water flows through the straw, then stop. Wait until the water stops flowing and dump that on a plant or somewhere. put the container back beneath the straw. (you need to do this between each object to make sure the water level is corrected).

Next weigh an object. We used a post office scale because thats what we had and it's good for light items.

We noted the weight on a piece of paper. Next we carefully dropped the item in the water. The item displaced the water which over flowed through the straw into the empty container. Our straw should have been angled slightly more downward but it wouldn't seal well and this was the best we could manage without any leaks.

When it stopped flowing we poured the over flow water into a measuring device more suited to small quantities. Then we noted the volume of displaced water.

To find the density of an object all you need to do is divide the mass (previously noted weight) by the volume (the displaced water just measured).

I cut the video off before we calculated the actual density by mistake - oops!

No comments: