## The Poly Density Bottle

by: Tami O’Connor

So, do you ever bring discrepant events into your classroom to capture your students’ attention? If so, the Poly Density Bottle should be on your list of must-haves! As you can see, this is a one-liter bottle filled with clear liquid. Floating at mid-bottle are two bands of beads, with blue on top of the white.

On its own, this is intriguing to many students. The head scratching begins, however, once the bottle is given a good shake. As soon as everything starts to settle, students will observe that the white beads now float at the top of the liquid while the blue beads sink to the bottom. The liquid, once clear, now appears to be slightly cloudy.

But wait, there’s more… After about 30 seconds something interesting begins to happen. The white beads gradually sink down, the blue beads gradually begin to float up, and the liquid above and below the beads is again clear. Now the stumper… Why is this happening? Read the rest of this entry »

## Teaching the Periodic Table

#### Teaching with a 3D Model of the Periodic Table?

by: Roy Alexander

Who knew?

I never realized how easy is would be to teach with my 3D periodic table until I started listening to a science teacher at last year’s NSTA convention.

She recognized that the AAE (Alexander Arrangement of Elements) she was walking over to at my lunch table was pretty much the standard chart: rolled and folded (I knew that) and that the common 2D element arrangement is the same thing unrolled and unfolded with the familiar separations and multi-gaps. (I knew that too: it’s what I started with when fixing the gaps that annoyed me so much.)

She (Allison) said that she’d had to make her own 3D periodic table ever since her professor showed her how much better it is for introduction of the idea for middle and high school students. That’s when I began to get a glimmer of its usefulness in the classroom – beyond the motivation of novelty and appeal of the logic I used to develop it!

The photos, she told me, bring reality to the common abstract chart, and are a terrific way to have the least academic of her students to immediately identify where metallic elements are, and by seeing, for instance, the Noble Gases looking like downtown at night.

She pointed out that the Main Group element’s ability to stay as a unit all the way to the last period would make her job of teaching trends simpler – as they are most obvious that way.

(I had NO idea!)

Earlier I’d learned that although Mendeleev got only half of his missing element predictions correct, being the first to leave space for the undiscovered was pretty gutsy, giving him the right to state “…the elements if arranged according to their atomic weight…” in his Periodic Law. Read the rest of this entry »

## Energy Sources in a Classroom

#### Energy Sources in a Classroom – Scavenger Hunt

by: Roy Bentley

I had the opportunity to attend the NSTA Convention that was held last month in Boston. It was a great show with amazing displays, topics and speakers. And of course, we had the PowerWheel there demonstrating how easy it is to teach about energy.

One of the points that came up during the show that struck me as worth exploring further was when we asked the teachers we were working with was “what sources of energy do we have in the classroom” The teachers at the show answered the lights, the power outlets, the sunshine through the windows and possibly the forced air from the heating/cooling system. No one referred to the faucet. When the teachers were asked if they had ever had the electricity fail in the school they all answered yes. When asked if they had ever experienced a water failure in the school they all answered no. It was concluded that the most reliable source of energy in the room was the faucet/(gravity).

Here is a simple classroom or home activity to help students realize how many energy sources are around them all the time! Read the rest of this entry »