Ninth Grade Science Experiments (Page 131)

Science Fair Project Idea

Scientific Method

Sometimes, simple toys can be quite complicated. Take the yo-yo. It's a fun toy and there is nothing simpler than a string wrapped between two connected disks. But there's a lot of physics that makes a yo-yo work. In this science fair project, learn more about how and why a yo-yo works. You will investigate the effect of string length on the yo-yo's "sleep" trick time. If people ask why you've got a yo-yo with you all the time, tell them that while it looks like you're just having fun, you're… Read more

How Low Can It Go? Design a Kite that Flies Best in Low Winds

Science Fair Project Idea

Scientific Method

Flying kites is an excellent way to learn about aerodynamic forces. In this science fair project, you will build and test a variety of kite designs to see which flies best in low wind speeds. You will use an inexpensive anemometer to accurately measure the wind speed. Since you will be choosing which kites to build and test, the experimental procedure provides a general outline for the experiments, but there is a lot of opportunity for you to be creative with your kite designs. This is a DIY… Read more

How Many Cranks Does It Take to Power a Hand-Cranked Radio?

Science Fair Project Idea

Scientific Method

If you lose power, you can probably still access the internet and read the news with a cell phone. But what if the power goes out for so long that your phone battery dies, or if cellular service also goes down? How would you get news from the outside world? In emergencies, you can use a hand-crank radio, which is powered by manually turning a crank. But just how much power do you get when you turn the crank? How long will the radio stay on before you need to charge it again? Try this project to… Read more

How Many Seeds Do Different Types of Fruit Produce?

STEM Activity

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Do you like your strawberry jelly with or without the seeds? Are you glad to have a seed-free watermelon, or do you enjoy spitting the seeds into the garden? You might not like finding seeds in your fruit, but fruit is a plant's tool for dispersing seeds to create offspring. In this activity you will investigate how many seeds can be dispersed for each type of fruit. Based on the number of seeds they produce, how productive do you think some of your favorite fruits are? … Read more

How Much Weight Can Your Sandcastle Hold?

Science Fair Project Idea

Scientific Method

Do you think a sandcastle can support a brick? How can you change a sandcastle to make it support more weight? Find out in this fun science project! Read more

How Much Worm Is a Worm?

Science Fair Project Idea

Scientific Method

Worms are slimy, wiggly, and gross. But did you know that they have many unique abilities? One of the neatest things that worms can do is regenerate, or re-grow, parts of their body. After a piece of a worm is cut off, it can grow back with all of the necessary new parts. How much of a worm can you cut off and still get regeneration? Is one end of the worm better at regenerating than the other? See if you can make heads or tails of this wiggly problem! Read more

How Quickly Does a Tennis Ball Lose Its Bounce?

Science Fair Project Idea

Scientific Method

The rebound rating is the ratio of the height the ball bounces to, divided by the height the ball was dropped from. Use the rebound rating to measure the bounciness of new tennis balls vs. balls that have been used for 10, 20, 50, and 100 games. Another idea to explore: does it matter what type of court the ball is used on? (See: Goodstein, 1999, 63-64.) Read more

How Secure Are Your Security Questions?

Science Fair Project Idea

Scientific Method

Many websites ask you to answer "security questions," like "What is your mother's maiden name?," to recover your account if you ever forget your password or login ID. However, sometimes the answers to those questions are easy to find online. Does this pose a risk to the security of important accounts like email and online banking? Are people even aware that this information about them is available online? In this project, you will investigate how secure people think security questions are, and… Read more

How Shoe Tread Affects Traction

Science Fair Project Idea

Scientific Method

Have you ever noticed that some shoes grip the ground better than others? The pattern and design of a shoe’s tread can affect how slippery it is on different surfaces. You can test shoes with different tread patterns—like flat, ridged, or patterned—to see which design provides the best grip. By dragging a shoe along a surface with a spring scale at a constant velocity, you can measure how much force is needed for each shoe to slide on various surfaces. With this knowledge, you… Read more

How Strong Is Your Hair?

STEM Activity

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Have you ever wondered how strong hair is? When we talk about our hair we usually discuss color, length or texture. But what about hair strength? If you look at a strand of hair, it looks like a very thin string. In fact, it is on average only about 0.1 millimeters thick. It doesn't seem like such a thin string could withstand much force. How much weight do you think a single strand of hair can carry? In this activity you will put a hair to the test and find out. You might be surprised by your… Read more

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