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

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My Pledge to Parents

One of my goals entering this new school year is to improve the teacher/parent relationship. After 15 years of teaching I have met many wonderful supporting parents, but I have to admit my view on parents has been tarnished by the few less than capable parents that I have encountered during that time. So I here is what I will pledge to all parents this coming school year.

  1. I will acknowledge that you know your son/daughter better than I do. I only have your child for 45 min a day. Granted, I see them in a different social context that you do, you actually have spent 11-12 years with them and you probably have more in depth knowledge of what they are like. I will use your insight to better help your son/daughter.
  2. As a student you have experienced many years of the education system and it may have been a negative and or positive experience and many of your fears and expectations are based on that. What you need the most is all the facts and information. The more information I can give you, the better you can make decisions. I will give you all the information about policies, procedures, standards, testing, grading, resources about my class and the school.
  3. I will contact you more. I will give you the positive information and the negative information, preferably in that order. I will do this mostly by email, since it more efficient than phone calls and more personable than the robotic phone dialing system that our school uses. Too often what you tell students during the day is not communicated on to the parent. I need to bridge that communication gap.
  4. I will respond to emails in a timely manner. During a busy school day it's easy to forget that you had to respond to that parent's email. On the flip side I will pledge to not respond quickly to a negative parent email. There needs to be a cooling off period, so that I can calmly and rationally respond to a hostile email. Sometimes it requires a good night's sleep and then cooler heads will prevail.
  5. I will presume positive intent. I will not prejudge the parent when the son/daughter does not meet expectations. Parents, you have the most challenging job in the world and you want only what is best for your child. I always need to remember that, and you are probably 10 times more frustrated with the situation than the teacher is.

I'm sure as the year goes on that I will have to adjust my pledge, but I think that this will be a good start and hopefully will lead to some good learning.


Video Demo: Flour Fireball

When chemicals burn, it is really a chemical reaction between the substance and the oxygen in the air. When substances do not get enough oxygen, they don’t burn completely. Below is a video of 30 ml of flour exposed to a flame. Only a small fraction of the flour burns, while the rest does not. The surface area of the flour is quite small and needs to be spread out.

If the flour particles spread farther out from each other, more oxygen will be able to react with them. The following demo does just that.

The three pictures below show the required materials.

Place the pie tin with candles on a chair so that the pie tin sticks out a few feet. The meter stick can be kept in place by placing a few books on it. Measure out about 50 ml of flour and place into the sifter. Stand on a chair and sift the flour so that it falls onto the candles. Caution: Wear goggles, lab coat (or apron), and keep flammable materials away. Have a fire extinguisher close by just in case. Do not use too much flour!


Video Demo: Colorful Water Electrolysis

In my class students learn about chemical reactions and also the difference between elements and compounds. Students learn that the 5 signs of a chemical reaction are: 1) color change 2) gas production 3) precipitation 4) temperature change 5) change in properties (smell, texture, taste, density, etc.) Students also learn that compounds are chemicals that have 2 or more elements bonded together, such as water. In this demonstration, students observe water undergoing a chemical reaction, and breaking apart into hydrogen and oxygen gas. This demonstration can be done on an overhead projector so that all students can view it easily. The materials needed for the demonstration are shown below.

This is a simple demo that doesn’t require any special equipment. As the electricity goes through the water, molecules of hydrogen gas and oxygen gas form at the separate ends. The bromothymol blue solution changes color only at one of the ends, indicating the gasses are not the same. More hydrogen gas bubbles appear on one of the ends as oxygen gas bubbles on the other end. This clearly indicates the ratio of hydrogen atoms to oxygen atoms in water is 2 to one. Tip: Dissolve some salt into the water to aid in electricity flowing through the water.


Reaction Bag

This is a lesson that I got from another teacher, who I think got it from Science Gems. My eighth graders have to learn what chemical reactions are and how to recognize them. Our textbook describes 5 types of evidence that a chemical occurred. They are color change, temperature change, gas production, precipitation and change in properties (like smell , taste, texture, etc.). In this lesson students have to look for which types of evidence occur when calcium chloride, sodium bicarbonate, and phenol red solution are mixed together. What is really cool about this lesson is that students get to feel the reaction. The chemical reaction takes place in a sealed plastic bag. It inflates because carbon dioxide gas is produced, it gets very hot, it changes from a red color to a yellow color (the carbon dioxide makes the liquid acidic), and the smell at the end is a chalk smell (calcium carbonate). Download the student handout and view the quicktime video (or Google Video) and pictures on how the lesson works.

Materials needed

Tips: Emphasize to the students to feel the solid chemicals immediately after all chemicals are mixed together so they are able to sense the temperature change.


The Reverse Balloon

One of my all time favorite demos. This is a variation on the crushing of the soda can via atmospheric pressure. I do this demo when studying the phases of matter. The molecules in a gas are rapidly moving in all directions and they are spaced as far apart as possible. When cooled to a liquid phase, the molecules come together as close together as possible thus taking up less space. This demo illustrates that.

Fill the 250 ml flask with about 50 ml of water. Set the flask on the hot plate and heat until water boils. Carefully take the flask off the hot plate with tongs. Carefully (don’t get burned) stretch the opening of the balloon over the mouth of the flask. Then with tongs, carefully transfer the flask so that the bottom half sits in ice water. Watch what happens!

The gaseous water in the flask quickly turns to the liquid phase. The molecules in the liquid phase take up much less space (volume) and the balloon gets pushed (sucked) into the flask and stays that way. Your students will be amazed.

Sometimes I show the end result to them first, and they are then challenged to test ways in which it can be done.

Precautions: Use tongs in this demo. The flask gets extremely hot.