Air Pressure: A Cup, An Index Card & Some Water

This is a pretty well-known, classic experiment when it comes to air pressure.

If you aren't familiar with it, you should be - it's easy to do in any setting.

Fill a cup part way with water. Place an index card on top (make sure the card is large enough to completely cover the cup).

Pick up the cup, placing one hand on top of the index card.


Turn the cup over, holding the index card up with your hand.


Ask your students what they think will happen if you remove your hand that's holding the index card.

Then do it!

There really is water in the cup, I promise! My hand got in the way of the water line...

Air pressure doesn't just push down, it pushes on things in all directions. In this case, air molecules are pushing on the index card. They exert more pressure than the water pushing down does, so the card stays up.

If something breaks the seal, or the index card gets too wet (as it will after enough time has passed), the card will fall and water will gush out!

Test Review Raffle

To encourage your students to participate in a class review (or other comparable activity), hold a raffle at the end. For every correct answer the student supplies, she earns a raffle ticket. The more correct answers, the more tickets, the better chance to win. If you're using this for a test review, the most coveted prize would be some extra points on the test. Otherwise, use something that works into your pre-existing system.

Raffle tickets are available at office supply stores or online. Or you could create your own.

Rate of Reaction: Glow Sticks

Background:
*Glow sticks work because of a chemical reaction.
Glow sticks contain two substances - one housed in the plastic casing and another inside a thin glass tube within the plastic. When the stick is bent, the glass breaks, allowing the two substances to react with one another. More information can be found here.

*The speed at which a chemical reaction occurs is dependent upon the temperature at which the reaction is occurring.
This is not the only factor that influences rate of reaction, just the only one we'll be talking about here.

For today's experiment:
You'll need two glow sticks* (two of the same color is best - makes it easier to compare), 2 glasses, hot water and cold water.

The water can come from the tap. I usually stick the glass of cold water in the freezer for a minute or two while I'm getting everything else ready, just to make it extra cold. I get as hot of water as I can from the tap. I suppose you could boil some water, but this works just fine and reduces the prep work.

Put your two glasses next to each other. Activate both glow sticks at the same time and place one in each glass.

Left side = hot water, Right side = cold water

After a minute or two, you'll notice that the stick in the hot water is glowing much brighter** than the one in the cold water. In fact, the one in the cold water will barely appear to be glowing.

Left side = cold water, Right side = hot water

The reaction that causes the glowing is occurring at a much more rapid pace in the hot water, thus the stronger glow.

Your students may have heard that they can save their glow sticks by placing them in the freezer. Doing so will slow down the rate of reaction, so the glow stick will last longer; but it doesn't stop the reaction, once the glow stick has been activated, it won't last forever, even in the freezer.
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*Keep your eyes on the dollar section of stores such as Target - you can occasionally find 12 sticks for a dollar there - makes it affordable enough to consider doing in the classroom.

**There really is a drastic difference in the 'amount' of glow being emitted from the two tubes, I promise. It doesn't photograph very well, at least not with my limited photography skills. So try it for yourself.

Microscopes: Cheek Cell Lab

View some animal cells under the microscope: your own!

Place a drop of iodine on a clean slide. Rub a toothpick along the inside of your cheek (not need to poke or jab, just a gentle rub). Dip the toothpick into the drop of iodine. Place a cover slip over the iodine and view under the microscope. You will note the irregular shape of the animal cell, as well as being able to identify the cell membrane and nucleus.

Mining: Birdseed Mining

This is based on an activity from the Women in Mining website. However, it not currently listed as one of their activities.

You'll need:
Bird seed mix (The mix will need to include sunflower seeds, and at least two other types of seeds. You'll need approximately 20 mL of birdseed for each pair of students.)

Small beads - "seed beads" - blue, gold and silver

50 mL beakers - 1 per pair of students

Prep Work:
For every 300 mL of birdseed, add 7 gold beads, 13 silver beads and 25 blue beads.

The activity:
Each pair of students is given 15-20 mL of prepared bird seed mixture.

Students search through the mixture and separate out (i.e. "mine") the sunflower seeds, millet, and beads, making piles of each.



Students count and record each pile of seed: sunflower seeds, millet, blue, gold, silver beads, and everything else (doesn't need to be separated, just counted).

Now for the math...
I typically provide my students with a data table (sometimes it's drawn on the board and they copy it into their notebooks, other times it's provided to them on a piece of paper).

I've tried to recreate said data table here, but have failed. Miserably.

So, here is a picture of said data table:
(I can't figure out why the photos is being rotated... that's just the way my day is going... I'm sorry, you'll have to turn your head, until I can figure out how to fix it).


Hopefully the picture makes things clear, but in case it doesn't, here is an explanation:

A dollar value is assigned to each of the mined substances:

Gold beads = Gold = $5
Silver beads = Silver = $4
Blue beads = Copper = $3
Sunflower seeds = Iron = $2
Millet = Lead/Zinc = $1
Other = Waste = n/a

Students will calculate the value of their mined materials by multiplying the number of pieces of each material by the value of the respective material.

Adding together these values will give students their Gross Income.

In addition, students will determine their expenses by multiplying the total number of materials (including waste - it costs money to dig up waste too!) by 0.23.

Gross Income - Expenses = Net Income (or Loss)

In addition, students can determine their % profit (or loss) with the following formula:

[Net Income (or Loss) / Gross Income] x 100

(In words: net income divided by gross income; that number multiplied by 100)

It's...

....a rock drill bit. This particular bit came from the Sterling Hill Mining Musesum in Ogdensburg, New Jersey.

Zinc was mined in northwest New Jersey until recently. It is also home to a highly concentrated number of fluorescent minerals. I highly recommend a visit if you're in the region. Many of the tour guides are gentlemen previously employed as miners at the mine - they provide quite a perspective as you tour the actual mine. In addition, there's a wonderful gift shop filled with various mining artifacts - I love my dynamite box! Great for school groups as well as families.

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What Is It? is a feature you can add to your classroom. Once a month, or thereabouts, put out something new and ask students to try to identify it. If they figure it out correctly, give them extra credit, a prize, a high five or bragging rights!

Observation: The Sense of Touch

Observations can be made with any of our senses (though, we tend to avoid the sense of taste in the science lab). This activity gives students a chance to test their sense of touch.

Number a bunch of socks with a permanent marker. Place a household item (non-breakable) into each sock.



Students will use their sense of touch to identify the objects. Students can feel the objects through the sock or, if the socks are long enough, reach their hand into the sock to feel the object without looking at it.

You can have students record their findings in any number of ways:
1. A list of words describing the object.
2. A sketch of the object's shape.
3. A hypothesis as to what the object is.

I often have students make a data table that incorporates 2 or all 3 of these pieces
of data (along with the sock number).

I like to have enough socks so that there's one for each student. To keep things moving and in order, I'll call out when it's time to switch socks, at which time, all the socks will move to the next person.

After students have observed all socks, I'll ask for their hypotheses for each sock number. Then I'll reveal what was actually inside.