How Does That Work? Wine Rack

The wine bottle appears to defy gravity in this wonderful gadget. I've been told you can find all variety of these in wine stores, online, etc. Or you can make your own (or have your dad make you one in celebration of your college graduation :) There are instructions throughout the internet, but basically, you take a slab of wood (mine measures about 9" long by 3 or 4" wide, cut a hole in one end,

and trim the edges so they are at 45 degree angles.

In a classroom setting, you'd obviously want to use some sparkling juice instead of wine. I believe that if you make the hole big enough, you could also use a 2L bottle of soda. I wasn't able to test it out - mine isn't large enough to accomodate such a large bottle.

The bottle holder works based on the principle of center of gravity - can your students figure it out?

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How Does That Work is a series of products and demonstrations that you can present to your students and challenge them to explain the science of how they work. Make sure you decide ahead of time what you'll accept as a valid explanation - can it be printed straight off the internet, written in the student's own words, or does the student need to be able to explain it to you conversationally? What will a valid explanation earn the student - a prize, extra credit, a feeling of goodness?

Air Resistance: Crumpled vs. Flat

Crumple one sheet of paper into a ball and keep a second sheet flat. Drop both pieces of paper from the same height.

The crumpled piece of paper will fall to the ground faster, because it has a small surface area, thus comes in contact with fewer air molecules and is subject to less air resistance.

Plants: Celery in Colored Water

You may have done this as a kid!

Cut about an inch off the end of a stalk of celery, so you have a fresh end. Place the celery in a cup of colored water and allow to sit for a few days while you observe.

Because the water is carrying food dye with it, you will be able to see the path the water takes as it moves up the stem and into the leaves. This provides a great visualization of the vascular system contained in most plants.


It’s also fun to place white daisies (or other white flowers) in colored water and watch the petals change color. I’d recommend doing the celery first, because you can see the xylem in the celery stem and therefore see how the water travels up the stem.

Moon: Phases of the Moon Demonstration

First, you'll need to create your prop:
Start with a large ball (playground ball, basketball, etc.) Use masking tape to mark the 'equator' around the ball. Paint one half of the ball white and the other half black.

For the demonstration:
Show the students the moon - explain that the sun shines on the moon, as it does the Earth, so that one half the moon is receiving light (the white side of the moon model) and the other half of the moon is in the dark (the black side of the moon model).

Then lay out the scenario:
The students, at their desks, are residing on the Earth.
The chalkboard/whiteboard at the front of the room is the sun (you could even draw a picture of the sun, if you wished).
The moon travels around the Earth, so you will carry the ball around the classroom, in a large circle that encompasses all of the students.

Remember.... the white side of the moon model always needs to face the sun!

Begin at the front of the classroom. Hold the moon so the white side is facing the sun. When the students, on Earth, look at the moon, they should only see the black side - this is the arrangement of the Earth, sun, and moon when there is a new moon.


Move to the back of the classroom. Hold the mood so the white side is facing the sun. When the students, on Earth, look at the moon, they should only see the white side - this is the arrangement of the Earth, sun, and moon when there is a full moon.


You can then move to the sides of the classroom, stopping at various points so students can see varying amounts of white and black, illustrating waxing and waning, crescents and gibbous moons, first quarter moon and third quarter moon.



You may wish to have students draw sketches of what they see as the moon circles the Earth.

Air Pressure: Collapse a Milk Jug

Heat some water to near boiling. Pour the hot water into the milk jug and swirl it around to heat the entire container. Pour the water out and quickly cap the milk jug. Within a few minutes, as the air inside the jug cools, the jug will collapse.

The hot water heats the air inside the jug, causing the air molecules to move faster and some of them move out of the jug. By capping the jug, you don't allow any air molecules to re-enter the jug and have created an area of low pressure. The pressure outside of the jug is greater, causing it to collapse.

Favorite Website: Science-Class.net

Lots of good stuff to be found on this website. You'll likely find some links to this site in some of my posts, sharing how I've implemented some of her ideas. But, I don't want to hold out on you, so check out the site yourself to find a whole cache of good stuff.

Refraction: Spot the Penny

Place a penny in the bottom of an opaque cup. Set the cup on a table or counter. Keep your eye on the penny as you step back from the cup. Continue to step back until you can no longer see the penny. Pour water into the cup (if you can reach, or have someone else pour it for you), and as it fills the penny will appear due to the refractive nature of water.

If you have difficulting with the penny moving while you're pouring the water in, you could glue the penny to the bottom of the cup ahead of time. You'll have it set up for years to come, and you'll know for sure that you're seeing the penny because of refraction, not because it moved.