Fourth Grade Science Experiments (Page 24)

Do Antibiotics Change Your Gut Microbiome?

Science Fair Project Idea

Scientific Method

There are thousands of bacteria in your gut that help you digest your food, recover important nutrients, and maintain your health. What happens to those bacteria when you take antibiotics? In this science project you will find out by accessing and analyzing a real data set of the gut microbiome (bacteria and other microbes) from healthy adults before and after they are given antibiotics. Read more

How Far Can You Throw (or Kick) a Ball?

Science Fair Project Idea

Scientific Method

Have you ever seen a "Hail Mary" football pass, where the quarterback tries to throw the ball as far as possible to reach the end zone and score a touchdown? Or a last second game tying soccer goal from midfield? How far the ball will go does not just depend on how hard a player throws or kicks it; it also depends on the angle at which the player launches the ball. In this sports science project, you will investigate how launch angle affects the distance that a ball travels by filming… Read more

Modeling the Chances of Getting an Autoimmune Disease

Science Fair Project Idea

Scientific Method

Do you know someone who has an autoimmune disease? Autoimmune diseases are fairly common, affecting more than 23.5 million people in the United States, which is about 1 in 13 people! You may have heard of some of them, such as diabetes (type 1), rheumatoid arthritis, and celiac disease. Many autoimmune diseases are poorly understood, but they all have one thing in common: they happen because a person's immune system (which normally fights off germs to keep the person healthy) attacks the… Read more

Nothing But Net: The Science of Shooting Hoops

Science Fair Project Idea

Scientific Method

Swish! What a great sound when you hit the perfect shot and get nothing but net. Here's a project to get you thinking about how you can make that perfect shot more often. Read more

Racing Bristlebots: On Your Mark. Get Set. Go!

Science Fair Project Idea

Scientific Method

Have you ever wanted to build your very own robot from scratch? Bristlebots are a cheap, easy, and fun-to-build robot made from the head of a toothbrush, a battery, and a small motor. Once completed, they buzz along the top of a table like bugs. How can you make a bristlebot go faster? In this project, you will build bristlebots from two different types of toothbrushes, and race them against each other to find out. Read more

Rocket Catcher Challenge

Science Fair Project Idea

Engineering Design Process

Inspired by real-world reusable rockets, in this engineering challenge, you will design and build a device to catch a falling rocket so it lands vertically. Drop the rocket from higher and higher heights to get a better score! The 2025 Science Buddies Engineering Challenge is over, but you can check out this page to see our other past engineering challenges and what this year's challenge will be! Teachers, lesson plan versions of this challenge are also available. Read more

Salty Science: Floating Eggs in Water

STEM Activity

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Have you ever wondered why some objects float on top of the ocean, and other objects sink to the bottom? It has to do with the density of the objects compared to the density of the salt water surrounding them in the ocean. If you add salt to plain water, it increases the density of the water. In fact, if you add enough salt, you can make the water so dense that an egg will actually float in it! Explore how this works in this science activity. Read more

Supercooling Water and Snap Freezing

Science Fair Project Idea

Scientific Method

Can water remain liquid below its normal freezing point? If it does, that water is supercool(-ed). This project shows you a method for supercooling water. You can test water from different sources to see whether or not it can be supercooled. Read more

Temper, Temper, Temper! The Science of Tempering Chocolate

Science Fair Project Idea

Scientific Method

Nut clusters, chocolate-dipped candies, and chocolate-dipped strawberries are just some of the delicious goodies that have a thin, rich layer of chocolate wrapped around them. But how do pastry and candy chefs make these delectable treats? The first step is to melt and temper chocolate. Tempering is a process in which the cocoa butter in chocolate is hardened into a specific crystalline pattern. When the cocoa butter molecules are in this pattern, the chocolate is shiny and breaks with a sharp… Read more

The Effect of Temperature on Chemical Reaction Time

Science Fair Project Idea

Scientific Method

Alka-Seltzer® tablets fizzle furiously when dropped into water. The moment the tablet starts dissolving, a chemical reaction occurs that releases carbon dioxide gas. In this science project, you can even measure how long and loudly your tablet fizzes using a smartphone equipped with a sensor app. Do you think you can make Alka-Seltzer fizz faster or more loudly by changing the temperature of the water? How big of a difference in the rate of a chemical reaction can temperature make? Read more

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