1. 100 ml of a 0.1 M NaOH solution is added to 350 ml of distilled water in a 500 ml graduated cylinder.
2. 10 ml of universal indicator solution is added, which turns the solution dark purple, indicating a highly basic solution.
3. An Alka-Seltzer tablet is added, which results in carbon dioxide bubble being produced. The carbon dioxide gas causes carbonic acid production, thus lowering the pH (more acidic). The solution starts turning green, then to yellow.
4. When the Alka-Seltzer tablet rises to the top (due to the attached carbon dioxide gas bubbles lowering the tablet’s density), add 10 ml of vinegar to the solution. This will cause a bright red color to be produced at the top, indicating high acidity (low pH).

Activation energy is the minimum amount of energy needed to start a chemical reaction. Many chemical reactions don’t need a lot of energy to react. A classic example when baking soda mixes with vinegar. The heat energy that is in the environment is enough to start this chemical reaction. Other chemical reactions need a higher amount of energy. A match lighting is one example. When a match strikes, the friction produces heat energy. This heat energy is the activation energy that starts the chemical reaction. In the following demo three matches are tied together with thread and placed into a flask that is covered with a piece of aluminum foil. The bottom part of the matches touches the bottom of the flask. The flask is placed on a hot plate on the high setting. The hot plate provides the energy to start the chemical reaction between the matches and oxygen that is in the flask.

This demo demonstrates that yeast do cellular respiration. When sugar (glucose) and oxygen are present, yeast mitochondria will make those chemicals react and release energy as well as the products water and carbon dioxide. Bromothymol blue solution will change to yellow in the presence of carbon dioxide. If there is no more oxygen, then yeast cells will shift to fermentation.

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.



Well here is the connection between Christmas and biology that I could make. I showed the students this candy cane and told them if they could name the shape that the red stripes make they would all get one. Most of them raised their hands and when I called on one, he said "double helix". We built DNA paper models this week and they learned its shape.

I'm not really.  It serves a purpose, but it fundamentally avoids the real problem. Districts should allow teachers access to the best tools available to enrich their classrooms and streamline their  workflow.  Blocking YouTube negates that. With TeacherTube in existence, districts feel justified in blocking basically the world's video archive.  I have experienced using TeacherTube and here are the downsides:

• Cumbersome uploading process.  Entering video information is a chore and uploading frequently fails.
• Video quality does not match YouTube.
• Ads inserted.  I know the site creators need to make money, but it's done in an extremely annoying way.
• Video choice is far less.

Here are the benefits of schools having access to Youtube:

• Easy to upload to.
• Superior video quality.
• Easy to search for video.
• Huge video library.  If I need a Bill Nye clip, a Mythbusters clip, a clip of the Hindenburg burning, anything, there is a good chance that it is there.

Is YouTube perfect?  Far from it.  My biggest complaint is in embedding videos. At the end of an embedded video there are the suggested videos that are frequently inappropriate for my students (middle school students).  This needs to be dealt with. I don't embed Youtube videos on my teacher page because of this this.  I instead upload videos to Blip.tv and link to the original download source material to avoid the suggested videos. YouTube needs to offer more control of this to its users.

My district unblocked YouTube, Blip.tv and other video sharing sites about a year and half ago and what were the results?  Students did not flock to YouTube during school time because there already is a school policy in place that instructs students to use the computer for school related purposes and not for personal entertainment. Teachers frequently walk around the computer lab room and/or classroom to monitor student activity and it works.  Imagine that.  Teachers as a result have been able to infuse into their curriculum a valuable resource.  That said, why am I writing about pulling the plug on Teacher Tube?  Our district seems to be in the minority.  When I collaborate with teachers outside the district, they frequently mention that they only have access to Teacher Tube. That is a shame. Districts please trust your teachers.  They will be responsible professionals. Don't treat them like children.

Teaching how the eyeball works usually involves showing diagrams of the eyeball and showing how light passes through the lens. Science teachers can also use Jello to make lenses that will show laser light refraction.  I tried that and had disastrous results.  I started to play around with mixing baby powder (mostly cornstarch) with red food coloring and water.  I was quite pleased with the results.  Go ahead and watch the video below to see what happens.

Tonic water might not be your first choice for a beverage, but it's the secret ingredient you'll need to make a glowing geyser. It turns out that tonic water will glow under a black light because tonic water contains quinine, a chemical that was originally added to tonic water to help fight off malaria in places like India and Africa. While the tonic water we drink today only contains a small amount of quinine, it's still enough to make your drink glow under black light. 

Instead of using mentos to make a glowing gyser, I decided to do a Hero's fountain version. You can get a simple apparatus from teachersource.com that fits into 2 2L bottles. Where in your curriculum can you fit this? In eighth grade science we cover properites of matter such as denisty, phase at room temperature, color, flame color, smell, texture, etc.  Some chemicals can be identified from the ability to fluoresce when exposed to uv light. I would maybe do this with a fountain of regular water and one with tonic water and then ask the students if the same chemical is in each founatin.

Sodium reacts exothermically with water: small pea-sized pieces will swim around the surface of the water until they are consumed by it, whereas large pieces will explode. While sodium metal reacts with water, you can observe that the sodium piece melts with the heat of the reaction to form a perfect sphere shape if the reacting sodium is small enough. The reaction with water produces very caustic sodium hydroxide and highly flammable hydrogen gas. In any case these are considered an extreme hazard and will cause severe skin and eye injury.

In the video below a small pea sized piece of sodium is placed into water. It does ignite and explode. To avoid an explosion ice water should be used. To avoid ignition a safer method can be used in which a layer of mineral oil is placed on top of the water. The mineral doesn’t react with the sodium and prevents ignition.

For a safer sodium demo, fill a large graduated cylinder with and equal portion of water and mineral oil. The mineral oil will be on top. When sodium metal is dropped into the cylinder it won’t react with the mineral oil and when it touches the surface of the water, it reacts briefly to produce hydrogen gas bubbles, thus causing it to rise back up into the mineral oil.