ScienceFix

Videos to Use in the Science Classroom

sciencefix — Fri, 15 Aug 2008 03:34:06 +0000

I’m a huge fan of NOVA Science Now. They produce short 12 minute videos that spark people’s natural curiosity and inject some solid science explanations. Two videos that I have recently watched are worth viewing and using in the science classroom.

The first video “Capturing Carbon” showcases a company that is trying to create an “artificial tree” to extra excess carbon dioxide from the atmosphere. The lead researcher got the idea from his daughter’s science fair project. She investigated if gaseous carbon dioxide could be extracted from the atmosphere. She inserted a tube, that was attached to a fish filter pump, into a container of sodium hydroxide. Carbon dioxide did indeed mix with the sodium hydroxide making the pH lower (more acidic). The father was intrigued by the results and wondered if he could scale it up successfully. The video indicates that they have made some substancial progress. This would be a good video to supplement the teaching of acids/bases and photosynthesis.

The second video covers some of the biological chemistry that the Phoenix Mars Lander is investigating. The water ice discovery is discussed, but less reported on is the nutrient and pH content of the soil. The pH is surprisingly slightly basic and the soil contains sodium, potassium, magnesium, and chloride levels similar to Earth, conditions that are favorable to microscopic organisms. This would be a good video supplement in the teaching of acids/bases and chemistry of living systems.

Video Demo: Flame Tests

sciencefix — Tue, 12 Aug 2008 03:58:19 +0000

Chemicals can be identified based on their characteristic properties. This is an updated version of my flame tests demo. I got the idea for this demo strangely enough from the AMC television show Breaking Bad. The main character in the show is a chemistry teacher, played by the terrific Bryan Cranston, (he also played Buzz Aldrin in From the Earth to the Moon). In the first episode he is in class showing the students how different chemicals burn different colors. He used spray bottles to disperse the chemicals across a Bunsen burner flame. I thought it was something that I definitely wanted to try out in the classroom, so I decided to give it a shot. I made the following solutions and put them in different spray bottles:

A. water only
B. 75 ml methyl alcohol only
C. 75 ml methyl alcohol, 4.5g of copper sulfate
D. 75 ml methyl alcohol, 4.5g of strontium chloride
E. 75 ml methyl alcohol, 4.5g of lithium chloride

Watch the video to see the results.

What color a substance burns is one property that can be used to identify a substance. Others include density, melting point, boiling point, hardness, etc. A flame test is definitely the most exciting property.

Periodic Table of Videos

sciencefix — Wed, 16 Jul 2008 20:40:20 +0000

I found a terrific website called the Periodic Table of Videos. Created by the University of Nottingham (yes that fabled town) chemists, the site has videos on 94 of the elements found in the periodic table. They try to demonstrate some of the properties characteristic of each element. Each video is on Youtube, which is unfortunate because many school districts block the site. Nevertheless it is an invaluable tool in teaching the matter and the periodic table to middle schoolers. Some of my favorite videos include:

sodium

iodine

mercury

Extract Your Very Own DNA

sciencefix — Fri, 11 Jul 2008 19:39:29 +0000

DNA extraction in the life science classroom usually involves isolating DNA from onions, strawberries, wheat germ, sweetbreads, etc. That tends to be kind of boring. More interesting to teachers and students is isolating DNA in humans. There are kits out there (like from BioRad) that you can buy for human DNA extraction, but they tend to be on the more expensive side, and thus aren’t practical for the classroom. I just came across a cheap method for human DNA extraction. The method comes from NOVA Science Now and it seems to involve cheap everyday chemicals. I haven’t tried it yet, but I’m definitely going to check it out. For printed version click here, for animation version click here.

Molecular Workbench: Chemistry Simulation and Modeling

sciencefix — Sun, 06 Jul 2008 22:24:11 +0000

I just downloaded, installed and played with Molecular Workbench. It is simulation and modeling software that students and teachers can use to understand what happens in various chemical phenomena. I could see using this on the computer and showing it on the LCD projector to students. At the middle school level you can use to to show phase changes, diffusion, atomic structure, chemical bonds and chemical reactions. Below are 4 demonstrations that I have recorded using Jing.

Molecular motion: gas

Molecular motion: liquid

Molecular motion: solid

Molecular motion: crystalline solid to a gas

Video Demo: Newton’s 3rd Law

sciencefix — Tue, 24 Jun 2008 17:59:19 +0000

Newton’s third law of motion states that for every action there is an equal and opposite reaction. The video shows one example of Newton’s 3rd law.

“Bad Astronomy” Videos

sciencefix — Tue, 24 Jun 2008 00:05:57 +0000

The Bad Astronomer, Phil Plait, is one of my favorite science bloggers. He mixes skepticism, science and humor into his work. He has produced 3 high quality short videos for Hulu.com. California 8th grade science standards include the universe and the solar system and these 3 videos are a good supplement. There are short commercials before the main content of the videos.

The first is about the changing landscape of Mars using videos and images from current Mars probes.

The second one covers super-massive black holes.

The third video covers galaxy interactions.

Video Demo: Whiteboard Protein Synthesis

sciencefix — Thu, 22 May 2008 14:12:14 +0000

Protein synthesis is the process that the cell goes through to make a protein from the information stored in the DNA. The video below shows a demonstration that you can do in your classroom to show how protein synthesis works. This demonstration emphasizes the following points:

1. DNA contains the information to make a specific protein.
2. The DNA is in the nucleus of the cell.
3. The DNA cannot leave the nucleus.
4. The ribosomes make the protein from the information.
5. The ribosomes are in the cytoplasm and cannot go into the nucleus.

The metaphor that I use in class is that the DNA is like a series of recipe books in the library. These books cannot be checked out/taken out of the library. The only way to get the information that is in the books out of the library is to make a copy. mRNA is the copy of the information that can leave the nucleus and go into the cytoplasm so that the ribosome can read and make the protein. Watch the video to see how it comes all together.

Teaching tips: Place the amino acids around the classroom (cytoplasm). Assign students to be specific tRNA’s. They will get the specific amino acid and bring it to the ribosome for you.

Lesson: Who is Your Closest Relative?

sciencefix — Thu, 01 May 2008 07:00:20 +0000

This is an activity where students examine the evolutionary relationships between 5 primates: human, chimpanzee, orangutan, gorilla, and gibbon. To determine the relationships students examine the DNA sequence of a single gene found in all 5 species. The DNA strips aren’t the real sequences, but they are based on real DNA match percentages. Students determine the percent base pair matches between each primate and human. They then construct a cladogram (a type of phylogentic tree) to show the the evolutionary relationships among the 5 primates. Watch the slide show on how to do the activity and download the student handout and DNA strips.

Lesson: Let’s Grub on Some Grass Beetles

sciencefix — Mon, 14 Apr 2008 01:12:01 +0000

Let’s Grub on Some Grass Beetles is a natural selection simulation. Natural selection is the “process by which favorable heritable traits become more common in successive generations of a population of reproducing organisms, and unfavorable heritable traits become less common.” In this activity, part 1 involves variations in silver beak loon beak types. There are tweezers, spoon, and knife shaped beaks. The beak best adapted to capturing grass beetles will survive and more chances to reproduce. The tweezers and spoon beaks are best adapted. The population of silver beak loons will change to a majority of tweezers and spoon beaks. Part 2 deals with variations in grass beetle color. The green grass beetles are best adapted to hiding in the grass than the orange or yellow grass beetles. In successive generations the populations of grass beetles will shift to green colors, since they will have the best chance to survive, reproduce and pass the variation to their offspring.

Watch the video and listen to the commentary on how to do the activity. Download handout: Let’s Grub on Some Grass Beetles