Third Grade Science Experiments (Page 102)

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 Numbers Can You Remember?

Science Fair Project Idea

Scientific Method

Are you good at remembering addresses and phone numbers? How many numbers do you think you can remember? Try this experiment to test your digit span, the maximum number of digits that you can remember. Read more

How Many Seeds Do Different Types of Fruit Produce?

Science Fair Project Idea

Scientific Method

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 to find seeds in your fruit, but fruit is the plant's way of dispersing seeds to make new plants. How many seeds can be dispersed for each type of fruit? As they say, in one end and out the other! 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 Current Does It Take To Blow Up An LED?

Science Fair Project Idea

Scientific Method

Have you ever accidentally burned out an LED while building a circuit? What about doing it on purpose—for science, of course! In this science project, you will intentionally send too much current through LEDs to see if they will burn out or even explode! How much current does it take to destroy an LED? How does this compare to the LED's rated current value? Try this project and find out! Check out this page for more LED science projects. Read more

How Much DNA Can You Pack into a Cell?

Science Fair Project Idea

Scientific Method

Have you ever tried to pack a suitcase? If so, you know that no matter how hard you try, there is a limit to the amount you can cram in, which means if you have more stuff, you need a bigger suitcase! Do you think the same principle applies to DNA in a cell? Does an animal with a bigger genome need a larger cell nucleus to store its DNA? Try this science project and find out! Read more

How Much Sugar Is Really in That Soda?

Science Fair Project Idea

Scientific Method

You know there is sugar in non-diet soda, but just how much sugar? Sure, you can look on the ingredients label, but how do food scientists actually measure the amount of sugar in a solution? They use a simple scientific device called a hydrometer. The hydrometer floats in the solution that is being tested, and the higher it floats, the more sugar there is! In this science fair project, you will use a precision hydrometer to measure the amount of sugar in soda. Read more

How Old Is That Rock? Roll the Dice & Use Radiometric Dating to Find Out

Science Fair Project Idea

Scientific Method

What do rocks and clocks have in common? Both keep track of time. Yes, radioactive isotopes present in rocks and other ancient material decay atom by atom at a steady rate, much as clocks tick time away. Geologists use those radioactive isotopes to date volcanic ash or granite formations like the giant Half Dome in Yosemite National Park. Anthropologists, archeologists, and paleontologists also use radioactive isotopes to date mummies, pottery, and dinosaur fossils. Does this sound abstract and… Read more

How Particle Size Determines Chemical Reaction Rate

STEM Activity

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Did you know that flour can explode? Luckily, this does not happen spontaneously on your kitchen counter, but only if the conditions are right. The trick is that you need a very fine powder of flour to make an explosion happen. In fact, any solid flammable material that is dispersed in the air as a dust cloud will explode once it is ignited. Why is that? It has to do with the particle size of the solid material, which determines how rapidly a chemical reaction takes place. In this activity, you… Read more

How Salty is the Sea?

Science Fair Project Idea

Scientific Method

Have you ever been swimming at the beach and gotten some water in your mouth by mistake? Then you know that the ocean is very salty. But what about other bodies of water? How much salt do they have compared to the ocean? Read more

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