October 5, 2012

Physical changes, chemical changes, mixtures, Goop and Oobleck.

We did two labs this week, added to our large graphic organizer on matter, did a mix and match review of vocabulary, and had a quiz. We kept busy adding to our knowledge.

I forgot to take pictures as we did a lab to demonstrate that mixtures could be physically separated. I gave the class small samples of a mixture of sand, salt and iron filings. They then used their knowledge of the physical properties of these items to separate them. A magnet removed the iron filings. Water put the salt into solution allowing the sand to filtered from the salt water solution. The water was then boiled away and the students were left with salt.

 Here is a pic of some students during the Mix and Match. The yellow cards had the vocabulary words and the blue cards had the definitions.

Verifying that the matches were correct.

We've been studying mixtures, so we made some this week.  Students enjoyed exploring the unique properties of Oobleck., a homogeneous mixture of cornstarch and water.

Materials for Oobleck.

It has the viscosity of water sometimes.

When you apply pressure it becomes solid.

 Students enjoyed viewing these videos from the website "Instructables" which show people walking on Oobleck and how it responds to sound waves.

We also made Goop, which is made from a white glue and water solution that is combined with a suspension of water and Borax. This mixture creates a new substance that stretches, bounces and picks up colors from paper and ink.

Measuring the white glue solution.

Mixing after adding the Borax suspension.

This is where you hear "Gross!"

Having fun.

We took a quiz over mixtures and colloids today. We'll be moving on to substances next week. Stay tuned.