wind turbine kit,
blood type test,
In this issue:
- Build a Full-Size Igloo
- Build an Ice Cube Igloo
- Cold Snap Science Projects
- Science Links
Build a full-sized or model igloo (with or without snow!) and learn more about insulation by putting ice cream in a hot oven!
Build a Full-Size Igloo
What you'll need:
- Adult supervision
- Hard, packed, dry snow
- Rectangular plastic storage tub or other suitable mold
- Friends to help
- Snow shovel
What to do:
- Make sure you have someone with you at all times while building your
igloo, so if it collapses, you won't be trapped inside.
- Use your plastic storage tub or mold to shape snow bricks. The size igloo you
want to build will determine how many you need. Building igloos is hard
work, so you may want to build one only big enough to accommodate two seated
people. If you're ambitious, try to build make it big enough to lie down
- Use your shovel to dig out a pit from the area where you got the snow
for your bricks. This will be your cold sink hole and entrance, so it doesn't have to be
very large—perhaps a third of the size of your igloo's floor space and a
foot or so deep. It will be like a
short tunnel that you crawl down into then back up to enter the igloo. (see
- Now starting at one edge of the sink hole, flatten out a circular span
of ground. A fun way to do it is by making a snow angel. This flat area
should be the size you want your igloo to be.
- Assemble snow bricks in a circle around the edge of the flattened
ground. This is the base of your igloo's walls. Make sure the igloo is
accessible via the sink hole entrance. You may need to dig it out a bit
- Stack another row of snow bricks atop the first, overlapping blocks and
packing loose snow in the gaps as you build up and shape the walls into a dome.
Be sure to leave small gaps here and there to allow air in, so you can
breathe inside your igloo.
- For the final brick or cap, you'll need a brick slightly larger than the
hole. Have your adult supervisor or friend help you set it in place. Now
have one person go inside the igloo and wiggle and shape the brick to fit
snugly. You may have to chisel it down a bit.
- Continue to fill the cracks (but not all of them!) with loose snow. In
particular, leave a hole near the top.
- From the inside, smooth the walls out and create grooves running
floor-to-ground. These will catch water as it melts, so it flows down and
doesn't drip on you.
- With adult supervision, bring a candle inside and light it. This will
melt the walls a bit, which will strengthen your igloo when they refreeze.
At night, you may pour a glass of water on your igloo to strengthen it from the
The snow acts as an insulator, that is, something that is a poor conductor of
heat or electricity. So the heat in the igloo, from body temperatures, candles,
etc., can't escape through the snow walls. But what about the cold air? After
all, the temperature must be below freezing (32° F) in order to build an
igloo! That's where the sink hole comes in. First, since
it's lower than the rest of the igloo's floor, cold air settles into it while
warm air rises, filling the rest of the igloo. This occurs because warm air is
less dense than cold air since its molecules are more spread out than those in
cold air. Second, the angle of the sinkhole means
that wind can't blow straight into the igloo like it would if the entrance was
level to the rest of the igloo. All these factors work together to make the air
inside an igloo as much as 40-50 degrees warmer than the ambient temperature.
The small hole in the top of the igloo allows the hottest air to escape, which
is why the igloo doesn't melt completely.
Read more about insulation with this
edible science project that shows how ice cream goes in the oven without melting!
Build an Ice Cube Igloo*
What you'll need:
- 2-3 ice cube trays
- Slushy mix (made with a few ice cubes and tablespoons of water in the
- Baking sheet
- Freezer space
What to do:
You'll need around 50 ice cubes in various sizes. Make half the ice cubes
full sized. The other half should be an assorted sizes made from filling the ice
cube trays half and three-quarters full.
- Sprinkle salt on the cookie sheet. Make a circle with 12 ice cubes and
place in the freezer till completely frozen.
For the second row, dip one side of each ice cube the salt. Center each
cube, salty side down, on the seam between two cubes from the bottom row
(like brick walls). Use the slushy mix to carefully fill the gaps. Refreeze.
Repeat step 2 making each successive layer with smaller and smaller
cubes. Each new row should be smaller than the one before, creating a
dome. Refreeze as necessary. Continue until only a small hole in the top
Make a door two with parallel rows of ice cubes and smaller ice cubes placed on top.
Use slushy mix to fill the gaps.
Carefully pat a thin layer of slushy mix over the entire igloo and then
refreeze for 2-3 hours.
The salt works as an adhesive by melting the ice cube where you dipped it.
The melted part then "sticks" to the frozen cubes below. The salt works by
lowering the freezing point of the ice cube. Freshwater freezes at 32° F, but
saltwater freezes at 28.8° F. In order for the salty ice cube to stay frozen,
the side with the salt on it would need to be below 28.8° F. Since room
temperature is often around 70° F, the ice melts.
*This project adapted from
More Cold Snap Science