Seventh Grade Science Experiments (Page 65)

Death Rays: What Duration of Ultraviolet Exposure Kills Bacteria?

Science Fair Project Idea

Scientific Method

Ultraviolet light can damage DNA molecules. If a cell's DNA repair mechanisms can't keep up with the damage, mutations are the result. As harmful mutations accumulate, the cell eventually dies. How much ultraviolet light is too much for a bacterial cell? Read more

Distance and Constant Acceleration

Science Fair Project Idea

Scientific Method

Have you ever dropped something and wondered how fast it was moving while falling? If it was something fragile, like a cell phone, you might not have been thinking about this at the time — you may have been too busy trying to grab the phone! But you probably wanted to find out just how hard it hit the ground afterwards. We know that gravity forces an object to fall, but how does this affect how quickly something falls and how hard it hits the ground? For example, did the phone move faster… Read more

Do Oranges Lose or Gain Vitamin C After Being Picked?

Science Fair Project Idea

Scientific Method

Are oranges highest in vitamin C when they are fresh from the tree (or, in a pinch, the grocery shelf)? Does the amount of vitamin C in an orange change over time, after it has been picked? In this science project, you will find answers to these questions by measuring the amount of vitamin C in a solution using an iodine titration method. Read more

Does a Cell Phone Conversation Affect Reaction Time?

Science Fair Project Idea

Scientific Method

Does talking on a cell phone make one a more dangerous driver? Here is an experiment you can do to investigate whether reaction time is adversely affected by a simultaneous phone conversation. Read more

Dog Toys: What Makes One a Favorite or a Flop to Fido?

Science Fair Project Idea

Scientific Method

Got a pampered pooch in your household? Then you know how much most dogs love their toys. And not just any toy. It has to be that particular beat up ball, gnawed frisbee, or ratty not-so-plush-anymore bunny with only one eye and partial ear remaining. Seems that dogs, like people, have definite preferences for their play things. This fun project investigates what makes a toy interesting to a dog. In these experiments, you and your dog can have some fun while you learn about canine behavior… Read more

Do-Re-Mi with Straws

STEM Activity

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Have you ever wondered how a musical instrument produces the beautiful sounds that it does? To make a certain note, the instrument has to make a certain sound wave. Depending on the instrument, the sound wave that is made can be affected by changing the length of part of the instrument, such as the strings in a piano or on a guitar, or a trombone’s air column. In this science activity, you will make your own musical instruments using drinking straws and explore how changing the length of the… Read more

Electric Paint: Light Up Your Painting

Science Fair Project Idea

Scientific Method

Electric paint is a fun way to include a circuit with lights in an art project, but it presents a challenge not found in traditional electronic circuits. What happens if you change the length or width of your strokes of paint, such as by painting longer, curvier lines or using a thicker brush? Could this affect the electrical properties of your circuit? Try this project to find out! Read more

Electric Play Dough Project 3: Light Up Your Sculptures!

Science Fair Project Idea

Scientific Method

Have you tried our first and second play dough circuits projects? Are you a master circuit artist, ready to try something even bigger and better? Try this project to see if you can build a three-dimensional light-up sculpture. Read more

Excess Volume: Investigate the "Shrinking Liquids" Effect

Science Fair Project Idea

Scientific Method

Cooking, washing, and many industrial processes involve the mixing of liquids. How liquids behave when they are mixed is dependent on many factors. Sometimes, the mixing behavior of liquids can be quite surprising! For example, when you mix 50 mL of one liquid with 50 mL of another liquid, you might not end up with a 100 mL mixture! In this science project, you will explore this phenomenon, which we call the "excess volume" of mixtures. How do you think your mixing volumes will… Read more

Explore How Chromatography Can Unmix Mixtures

Science Fair Project Idea

Scientific Method

Did you know that mixtures can be unmixed? Chromatography is an analytical technique in chemistry to separate mixtures and identify each of its individual compounds. In this project, you will separate ink dyes found in different markers using a strip of paper, chalk and different liquids. By comparing different chromatography substrates and solvents, you will learn how different attractive forces between substances can affect the separation of a mixture into its individual components. Read more

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