It's the beginning of the year, and chances are you are starting off teaching or reviewing the scientific method. If you've looked around on the internet for scientific method labs, you will notice that the majority are not biology related. Don't get me wrong- building paper airplanes, measuring bubbles, and seeing how many water drops can fit on the surface of a penny are fun labs, but not directly related to biology. In my class I want students to understand from the get-go that we are learning about living things, so I want my first lab to reflect that. Here are a few labs that can start your year off right:
1. Pulse Lab- This is a great lab because there are almost no supplies required other than a stopwatch. In this lab students measure their resting pulse, and compare it to their pulse standing up and holding their breath. It is a great way for students to practice writing hypotheses, and identifying independent and dependent variables. Before beginning the lab I start with a class discussion about what your pulse is, why blood needs to be pumped through the body, and where blood cells are made.
2. Firework Milk Lab- I have seen this lab done at ALL ages. Even preschool teachers love this lab. But the beauty of this lab is that high school students still love it, and they can finally start to understand the concept behind the fun swirling colors. In this lab students pour milk into a petri dish, add some food coloring, and put a drop of soap in the middle of the dish. Once the soap enters the dish the food coloring starts swirling and creating "fireworks." The reason the soap begins to mix the food coloring around is because of the chemical structure of the soap. The soap molecule has a polar portion that likes to mix with water, and a nonpolar portion that doesn't like to be around water. The soap molecules react with the fat molecules in the milk and start swirling around, which is visible from the movement of the food coloring. The fattier the milk, the better a reaction you will get. It is fun to have students test whole milk and skim milk and compare the results.
3. Testing the 5 Second Rule- This is my favorite lab to begin the year with, but it requires a little prep work. While you can order sterile agar plates from any science supply site, it is much cheaper to pour your own. If you haven't poured your own plates before, there are a ton of youtube tutorials available to walk you through it. In this lab students get to design their own experiment that would test whether or not food is really safe to eat after being on the ground for 5 seconds. When you purchase this lesson from my TpT store you will get two versions. In the high school version students design their own experiment, write their own procedures, and choose their own independent variable (food type, surface that they drop the food on, etc.) In the middle school version the procedures are given and it walks the students through the lab step by step. If you have an incubator the plates can be ready in 1 day, if not then let the plates sit over the weekend. Students will love seeing how much bacteria is on their food! You can even take it a step further and have students try and kill the bacteria with different cleansers (soap, bleach, 409, etc.) and see which is the most effective.
What other scientific method experiments do you love? Leave them in the comments below!
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