You need to first observe the outside of the leaf. Study the shape, color and texture of the leaf. Though most leaves essentially work the same, they usually look very different. Some leaves may be large, while others are quite small. Some leaves may have a velvety sheen while others feel waxy. The reasons why some leaves are shaped differently and feel differently are based on an survival process. According to PSU.edu, "Leaves high in the tree canopy receive a great deal of sunlight. These leaves tend to be smaller in size (and, therefore, have reduced light absorptive surface area)...Leaves in the lower tree canopy are more shaded. These lower canopy leaves tend to be larger (more light absorptive surface area)." Studying the outside structure of your leaf gives you a lot of information.
There are many different ways to record your observations. This is an important part of your project. Recording your results after making an observation is part of the scientific process. You can take a rubbing of your leaf. This is one of the best ways to record what your leaf looks like. Tape your leaf to a flat surface to keep it still. Lay a piece of paper over the top of the leaf. Gently rub an unwrapped crayon over the paper where the leaf is. This will cause the imprint to transfer to the paper. Paste your leaf rubbing in your science journal. Another way to record your observations is to fill-in a circle that describes the leaf. Write the word, "leaf" in the middle of your circle graph. Around the outside of the word, write one to two word phrases that describe the leaf. Words like large, green and waxy coated are some examples of descriptive terms you can use.
The inner structure of your leaf has several intricate parts that work together. One of the best ways to view the inside structure of your leaf is to choose a leaf still attached to a flowering plant. A white daisy works well for this part of the project. Place the white daisy in a vase of blue water. To make blue water, fill the vase half full with tap water, then drop two drops of food coloring in and stir well. The flower will soak up the water, turning it blue. Upon closer observation you can see the inner parts of the leaf. Veins will be visible to the naked eye. These veins help deliver water and nutrients to different parts of the leaf. The chlorophyll inside the leaf makes food for the plant. This is nearly impossible to observe without advanced technology. You can, however, cut a piece of leaf up and place it under a microscope to see the parts of the leaf at a cellular level.
Recording your observations for the inner structure of the leaf is important. How the leaf carries water and nutrients should be documented. Record your findings by taking pictures of the daisy leaf after it has soaked up the blue water. Snip a leave and paste it in your science journal. Make written recordings of what you see inside the leaf after it has absorbed the blue water. Describe whether or not you see many veins, if they are large or small and if some leaves have more veins that other leaves. If you studied a leaf under a microscope, write down what you saw. What colors did you see? What shapes did you see? Your teacher will want to see your findings. Turn in all your work and observations at the conclusion of the project.