About

I made ScienceFix.com to share my favorite demos that I do in my middle school science classes.  

Contact Me
Search ScienceFix.com
Twitter
Delicious
Media that I like...
  • Something Funny Happened on the Way to the Moon
    Something Funny Happened on the Way to the Moon
    by Sara Howard
  • NOVA - Origins
    NOVA - Origins
    starring Neil Degrasse Tyson
  • Human Body: Pushing the Limits
    Human Body: Pushing the Limits
    starring Bray Poor

Entries in video (90)

Sunday
Jun142009

Video Demo: Burning Iron

Many of the demos that I use in teaching chemical reaction are taken from a terrific book called A Demo A Day–Chemical Demonstration Book. The book contains a year’s worth of chemistry demonstrations that are easy to follow and to use. This demonstration shows that when iron has a large surface area it can react with oxygen and burn easily. I first use the 9 volt battery and touch the ends to various steel surfaces. The students see that nothing happens. I then touch the battery to the steel wool (held by the clamp on the ring stand) and the battery provides enough energy to make the iron burn. The steel wool has a larger surface area than pieces of steel like the ring stand. The steel wool is exposed to more oxygen molecules. You can also use this as a conservation of mass demo. Simply place the steel wool in a plastic bag and measure the mass. After burning the wool (of course it shouldn’t be in the bag at this point) return the leftover material back in the bag and mass it again. The mass should be the same (although it might be greater afterwards, since oxygen has now bonded with the iron.).

Preparations: You may have to soak the steel wool in acetone for 15-20 minutes to remove the outer coating, so that the steel is exposed. Take the wool out of the acetone and left it air dry.

Saturday
Jun132009

Video Demo: Disappearing Cup

Many of the demos that I use in teaching chemical reaction are taken from a terrific book called A Demo A Day–Chemical Demonstration Book. The book contains a year’s worth of chemistry demonstrations that are easy to follow and to use. This demonstration shows the concepts of polymers. Styrofoam is an example of a polymer. A polymer is made up of monomers. You can think of a monomer as a Lego piece. When you connect the Lego pieces together you have a polymer. You can take a Styrofoam cup and place it in a petri dish of acetone. Push down on the cup and the cup seems to disappear! The acetone is breaking the bonds between the monomers.

Precautions: Acetone is flammable and needs to be used in a well ventilated area. Wear goggles.

Watch the Google video.

Thursday
Jun112009

Video Demo: Glowing Penny

Another great demo from the Demo a Day: Chemistry Demonstration Book. To get chemical reactions started activation energy is needed. During a chemical reaction, heat energy is often released (exothermic) or absorbed (endothermic). To get this reaction started, a pre 1982 penny is heated over a Bunsen burner. The penny is wrapped in copper wire and held over the flame with tongs. Once the penny is heated, it is then placed into the 125 ml flask that contains a small amount of acetone liquid at the bottom. The penny does not touch the acetone, but is just above the surface. The copper in the penny reacts with the acetone fumes to produce a very exothermic reaction where the penny glows. The penny will continue to do this for several minutes.

Preparations: Make sure you adjust the penny and the copper wire so the penny just sits above the acetone. Do this before you heat the penny.

BubbleShare: Share photos - Play some Online Games.

Wednesday
Jun102009

Video Demo: Diffusion

See 2 video demonstrations of diffusion in action. The first video shows a drop of food coloring diffusing through water. It is a video that is time lapsed at 1 frame/15 seconds. The second video shows a Ziploc bag of iodine placed into a beaker of starch water. It is a video that is time lapsed at 1 frame/30 seconds. The iodine diffuses out of the bag and into the starch water. Where the iodine is diffusing the starch water turns a dark blue.

Sunday
Jun072009

Video Demo: Cola Volcano

Signs of a chemical reaction include color change, gas production, temperature change, precipitation, and other changes in properties …including density, taste, texture, smell, melting point, boiling point, etc. This demonstration will really make them think about it. Place a large plastic container on the counter. Invert a large jar or beaker into the container. Set a 3/4 full liter of fresh cola on top. Carefully but quickly pour a cupful of sugar into the soda and stand back. The cola will burst out of the bottle. Most students will assume it is a gas production sense they can see all of the foam. Have the students taste the left over soda. It is very sweet and very flat, indicating the soda is still there and the carbon dioxide left. It is a physical change and not a chemical change. The sugar pushes out all of the carbon dioxide gas.

Page 1 ... 14 15 16 17 18