Biology experiments
Middle school biology:
8 observation and control experiments.
From cells under a microscope to an energy pyramid built on a desk. What makes a biology experiment work is the control and the record, so each of these guides sets out a full control design and an observation table.
Cells & Plants
Onion Skin Cells Under the Microscope: Making and Observing a Wet Mount
A paper-thin film peeled from inside an onion turns into rows of neat little "boxes" under the microscope. Each of those boxes is a plant cell.
Five Cups of Mung Beans: What Do Seeds Really Need to Germinate?
Water, air, temperature, light — which of these does a seed actually need to sprout? Set out five cups, wait three days, and the answer grows by itself. One result will probably not be what you expected.
Green Leaves Make Starch in the Light: The Classic Half-Covered Leaf Experiment
On the same leaf, the half that saw sunlight turns blue-black with iodine, while the half hidden under black paper doesn't change at all. Two colors on one leaf — proving two things at once.
Put a Plastic Bag over a Branch: A Bag of Water Drops Reveals Transpiration
More than nine-tenths of the water a plant's roots take in never stays inside the plant — it escapes through the leaves. One clear plastic bag is enough to make this invisible water route show itself.
Life Processes, Heredity & Evolution
Seal a Jar of Sprouting Seeds: Proving Respiration with a Candle, Limewater and a Thermometer
Put germinating seeds in one jar and boiled seeds in another, seal both overnight, and run three tests the next day — a candle, limewater, a thermometer. The differences between the two jars are the textbook respiration equation, line by line.
A Genetics Experiment with Two Coins: Where the 3 : 1 Ratio Really Comes From
One coin plays the sperm, the other the egg. Toss them a hundred times, and the ratio Mendel spent years counting appears in your own notebook.
Natural Selection in a Paper-Chip Game: How Survival of the Fittest Happens
Scatter equal numbers of green and red paper chips on a green tablecloth, then pick up as many as you can in 15 seconds. Which color goes first? Repeat a few rounds, and evolution happens in your own hands.
Build an Energy Pyramid from Rice Grains: Why Food Chains Can't Get Too Long
1,000 grains of rice stand for the grass's energy. Only 100 make it to the rabbit; only 10 reach the hawk. How many are left at level five? Lay it out once and you'll see why food chains run out of room.
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