If you like looking at trees, and bark, and the pattern of veins in leaves; if you are fascinated by clouds or the spots on a ladybug’s back; if you like to split open rocks and see what’s inside, then you are already an outdoor scientist. The best part is you don’t need any special or fancy equipment, you don’t need to remember a charger, you just need your eyes and the power of observation.

Are there one or two sets of paw prints in the snow? Three or four kinds of birds having a conversation in a grove? What kinds of plants are strong enough to push their way through the cracks in the sidewalk? You may not always find the answer, but these are the questions an outdoor scientist asks about the world.

As summer approaches, here are five projects and experiments to lead you on your scientific journey into the natural world.

Make your own crystal

One way crystals form is when magma, or liquid rock, begins to cool. Different kinds and colors of crystals will form depending on factors like the temperature of the liquid and the amount of time it takes to cool. It’s the same process with snowflakes, also known as snow crystals. You can observe crystallization up close if you leave a solution of water and salt out all night at room temperature. The water will evaporate, and the salt will crystallize.

You’ll need:

• Pot to boil water

• 1 ¾ cups water

• ½ cup crystal or Epsom salt

• Glass jar or large glass

• Food coloring (optional)

• Thick string

• Pencil, butter knife, Popsicle stick, or any thin stick

Instructions:

1. Bring water to a boil in a pot (adults can help with this if you’re not allowed to use the stove yourself).

2. Stir in salt, adding until it no longer dissolves. The water should look almost clear with a few grains of salt swirling around (which means you’ve added slightly more salt than the water can absorb).

3. Transfer the solution to a jar.

4. Add a few drops of food coloring if you want to make colored crystals.

5. Tie one end of your string around the middle of your pencil and lower the other end of the string into the jar. The string should be long enough so that it almost touches the bottom of your jar.

6. Balance the pencil across the top of your jar.

7. Crystals should start to form in one or two days.

Capture a Paw Print

Dogs and humans go way back. Just as we evolved from primates, dogs evolved from wolves. Dogs were the first animals to live with humans. We call this domestication, which describes how a wild animal becomes our furry friendwatching Netflix beside us on the couch.

Today, there are over 300 breeds of dogs, but even after thousands of years of evolution, a dog’s paw and a wolf’s paw are still so similar that you can’t really tell them apart.

You’ll need:

• Newspaper

• Measuring cups

• 4 cups plaster of Paris

• 2 cups cold tap water

• 7-cup plastic container

• Mixing spoon

• Disposable aluminum cake pan, about 9 inches x 9 inches x 1 ½ inches

• Spatula

• Dog, cat, or any other animal

Instructions:

Warning: Never completely submerge your hand or a pet’s paw in plaster of Paris, and remove it quickly while still moist. Plaster of Paris gets hot when it dries and you don’t want to get stuck.

1. Spread out newspaper on your work surface.

2. Place plaster of Paris and water in a plastic container, and use your mixing spoon to stir well until your mixture is the consistency of pancake batter.

3. Pour the mixture into the aluminum cake pan and smooth it with a spatula. Let it rest for an hour to set.

4. Place your dog’s paw (or the paw/ foot of any other animal) onto the mixture and press it down about ½ to ¾ inch — press firmly. Your dog will probably be more cooperative if you set the plaster of Paris container on the table and the dog on your lap. Remove dog’s paw and rinse thoroughly.

5. Allow the plaster of Paris to dry for 24 hours, and you’ll have a life-size keepsake of your pet’s paw.

Note: If you don’t have any domestic or outdoor animals, you can always use a human “paw.”

Measure a Tree

You’ve probably learned that you can figure out the age of a tree by counting its rings, but each ring is really made up of two parts. One entire year is represented by a lighter band of a layer of tissue known as cambium and a thinner, darker band of cambium measured together. The light-colored band shows growth during the warmer, rainier months and good growth conditions. The dark-colored band shows growth during the colder months and difficult conditions.

Trees grow outward, meaning that the center of a tree is the oldest part, and the outer rings the newest. The central core, or heartwood, is the strongest wood in the tree even though it’s no longer alive.

Because human records of daily weather conditions only go back so far, trees serve as useful tools for scientists studying climate change. Trees often live hundreds of years and can tell us about weather conditions long before humans started keeping track.

You’ll need:

• Cloth tape measure

• Tree

• Calculator

• Google or a guide to trees

More information on tree growth can be found in “How Old Is My Tree?” by Lindsay Purcell, which you can find at purduelandscapereport.org.

Instructions:

1. Measure the circumference (distance around) of your tree at approximately 4.5 feet from the ground with your cloth tape measure.

2. Use your calculator to divide that number by 3.14 (which is, approximately, Pi).

3. Multiply that number by the “growth factor” of your tree. The “growth factor” is an average estimate of your tree’ species’ growth over time. The International Society of Arboriculture has published a table of growth factor numbers according to tree species that you need to search for on Google or look up in a guide to trees to complete the formula for measuring your tree.

4. The result is the age of your tree. For example: If your silver maple is 20 inches in circumference, and you divide that by 3.14, you get 6.369. Multiply that by the growth factor (3) and get 19.108. That means your tree is approximately 19 years old.

Make a Constellation Map

The night skies have always been important to humankind, primarily as a navigational tool.

Today, stargazing isn’t as easy as it used to be. The main reason is light pollution. When we think of pollution, we tend to focus on water and air pollution because they directly affect what we drink and breathe. But light pollution has long interfered with our ability to see the night skies in cities and suburbs.

An exciting citizen science project that you can participate in involves capturing the night sky from where you live and sharing it with people across the globe to track light pollution. To take part, visit the website Globe at Night.

You’ll need:

• Flashlight

• Drawing compass

• 2 pieces of 8 ½ inch x 11 inch (80-lb.) black cardstock

• Pencil

• Scissors

• Tape (optional)

• Pictures of constellations (either online or in a book)

Instructions:

1. Measure the circumference of your flashlight’s lens with a drawing compass. Copy the measurement onto cardstock with your pencil.

2. Cut out a few circles for different constellations. These should fit snugly over the lens and inside the lip of the flashlight (if your flashlight doesn’t have a lip, you can use tape to hold it in place.) It is important to leave a tab on the circle a little larger than a pencil eraser to pull your circle out of the flashlight’s rim.

3. Find images of constellations on the internet or in a book about astronomy.

4. Using your pencil, mark dots on your circles that look like your constellation images.

5. Using the points of your scissors, punch holes through the dots.

6. Insert one disc into the top of your flashlight. Turn on the flashlight in a dark room and shine it on a blank wall or ceiling. Enjoy viewing your constellation!

Make a Pine Cone Bird Feeder

Birds need four basic things: food, water, shelter, and a place to lay their eggs. For most common backyard birds in North America, such as the goldfinch, blue jay, robin, hummingbird, cardinal and sparrow, their diet consists of nuts, seeds, fruit and nectar. Ospreys, large coastal birds, like fish and will plunge into the water to scoop them up. Up the food chain: Herons like frogs, roadrunners like reptiles, hawks will eat other birds, owls like rodents and vultures will eat just about anything, including roadkill.

You’ll need:

• String

• Pine cone (f you don’t live near pine trees, you can buy a pine cone at a local crafts store)

• Birdseed (can be purchased at a grocery or pet store)

• Plate

• Honey

• Butter knife (optional)

• Branch or other place to hang feeder

Instructions:

1. Tie a string around a pine cone’s top so you can hang it up later.

Pour about an inch of bird seeder on a plate, enough to roll your pine cone in.

3. Drizzle honey over your pine cone. (Do this over the plate to catch any honey that drips off your pine cone.)

4. Once your pine cone is covered in honey, roll it around in birdseed on your plate until it’s covered. You many need to use a butter knife to get into the nooks and crannies.

5. Hang your pine cone from a branch and move a safe distance away to observe the birds that come to dine.

From “The Outdoor Scientist” by Temple Grandin, Ph.D., published by Philomel Books, an imprint of Penguin Young Readers Group, a division of Penguin Random House, LLC. Copyright © 2021 by Temple Grandin.