Video Demo: Carbon Dioxide Extinguisher

This video demonstrates some of the properties of carbon dioxide gas. Carbon dioxide gas is more dense than air. The gas can be poured kind of like a liquid. The video shows carbon dioxide gas being poured to extinguish a candle flame. A candle flame needs oxygen gas to burn. Since carbon dioxide gas is surrounding the flame, the lack of oxygen gas makes the flame go out. You could also use dry ice as a source of cargon dioxide instead of vinegar and baking soda.

materials needed

large poster board folded

video

Lesson: Rainbow Volume

An important component in learning matter, is being able to measure how much space matter takes up–in other words volume. Measuring the volume of liquids requires the use of a graduated cylinder. Students need practice to use the graduated cylinder effectively. My colleague, Cindy Giove, shared the lab activity, Rainbow Volume with me. It is a fun way for students to practice and an easy way for teachers to assess their growth. Students first start out with beakers of blue, red, and yellow water. They then measure a certain amount of colored water into each test tube. If they follow the directions carefully, and do the measurements accurately they will end up with test tubes with 11 ml of red, orange, yellow, green, blue, and purple water. Download rainbow volume handout. Download rainbow volume key.

Materials: beakers of red, blue, and yellow water, and a 25 ml graduated cylinder

Materials: empty test tubes at the beginning

End results: colors and equal volumes

Video Demo: Reaction Chamber

This is a demo that I only show the video. This is an example of what happens in the reaction chamber of a liquid fuel rocket. I use about 100 ml of denatured alcohol. I pour it into the 5 gallon plastic bottle. I swirl it around vigorously, trying to speed up the evaporation of the alcohol. I pour out the excess liquid alcohol. I then set the bottle on the counter, making sure it is flat. With a candle attached to the end of the meter stick, I insert the candle in the opening of the bottle. Again, I only show the video of this to my students and don’t do it live. It demonstrates the volatile reaction that occurs with oxygen in the air. The resultant hot gasses funnel through the opening (nozzle on a rocket) at a higher speed. This demo also shows when the particles of a chemical are spread out (increased surface area), the speed of a reaction increases.

ONLY TEACHER DEMO! I ONLY RECOMMEND TO TEACHERS THAT THEY ONLY SHOW THIS VIDEO IN CLASS AND DON’T DO THE DEMO IN CLASS. NEVER, EVER USE A GLASS BOTTLE! ONLY USE A PLASTIC BOTTLE.

Video Demo: Water Up

An inverted 100 ml beaker is placed inside a 400 ml beaker filled with colored water. The 400 ml beaker is placed on a hot plate. The water boils for a while, and then the beaker is removed. The water vapor inside cools condenses back into liquid. The molecules of a liquid take up less space than a gas, and therefore the pressure inside lowers. The atmospheric pressure pushes the colored water up inside the beaker. This demonstration can be found in Tik L. Liem’s Invitations to Science Inquiry.

Genetic Engineering in the Classroom

Genetic engineering may be the single most important development in biology in the last 20 years. Bio Rad is a terrific Bay Area company that sells easy to use kits that can be used in the classroom. Bio Rad’s pGLO transformation kit (see below) essentially allows students to insert the Green Fluorescence Protein (GFP) from a jellyfish and insert it into E. coli bacteria. With this inserted gene the bacteria make GFP and thus the bacteria glow green under UV light. The name of the kit is the pGLO Bacterial Transformation Kit. For detailed explanation of the kit, see video below.

pGLO kit

kit contents

video demonstration of kit