7th Grade Science Fair Project Ideas
Heat, Cold and Microorganisms.
We already suggested some basic microbiology experiments on our bread mold science project page. This 7th grade science fair project experiment is a little bit more complex. You're going to study how microorganisms react to temperature stress. Which conditions they can survive better - heat or cold?
Yeast is easily available, safe and easy to handle model organism for this experiment.
- coca-cola bottles (or other fizzy drink bottles)
Here is experiment outline:
- Prepare 6 samples of yeast. Use the same amount of yeast and water for each sample. Do not add sugar to the yeast solution.
- Wait for 5-10 minutes for yeast to activate.
- Put two samples in the refrigerator and freeze them. Unfreeze one in few minutes after water is completely frozen, leave another one in the refrigerator for 24 hours.
- Put 3 samples in hot water (60C). Keep them in hot water for 5, 15, and 30 minutes. Bring samples back to room temperature.
- It's not necessary to prepare all the samples simultaneously.
- The last sample is your control sample.
- Add sugar solution to the control sample and measure it's activity by measuring the amount and rate of gas production.
- After temperature treatment add sugar to the experimental samples, measure the amount and rate of gas production.
The yeasts activity measurement is similar to one in 5th grade science project.
Paper chromatography method allows you to separate different components from a mixture. For example you can check if colored markers are made of one color ink or a mixture of different inks. This project is easy to do at home. Experimental part of the science project will take a few hours, or less if everything is going just right. All you need is coffee filters, solvents (most of them are used for cleaning) and colored markers to separate. Read more about separating components of the black water marker using paper chromatography.
Temperature and the rate of a chemical reaction.
This 7th grade science fair project is an example of basic study of chemical kinetics. It's one of the fun science projects that you can easily complete in 24 hours.
The goal of the project: to study dependence between temperature and the rate of a chemical reactions. It's well known that generally reactions run faster as temperature increases but is it a linear dependence? Is this dependence the same for all chemical reactions?
It's easy to find out.
Constants: volume of reagents, physical state of the reagents, reagents interface.
- Tablets of alkaseltser.
- White sugar cubes.
- Thermometer (thermometer should be able to measure temperature in 0C-100C range).
You'll need to measure the rate of the reaction at different temperatures for the different reagents. We suggest to use 10 degrees span in temperature between samples with lowest temperature ~1C degrees and highest temperature ~99C degrees.
For each temperature sample.
- Put a tablet of alkaseltser in the glass of water. Measure time needed to fully dissolve the tablet. Measure water temperature change.
- Put a cube of sugar in another clean glass of water with the same water temperature. Stir water with the spoon (make sure that the stirring is the same in all samples). Measure time needed to fully dissolve the sugar. Also measure temperature change in the sample.
- Repeat this procedure for all temperature samples.
- Build the graphs.
Does curves for alkaseltser and sugar look the same? How does temperature affect the speed of the reaction? Is the change of the temperature the same for both substances?
Finding the best insulation.
Different materials have different insulation properties. Knowing this property is important for engineer and architects. Proper insulation of the house can decrease heating energy costs and help to protect our environment. Make a hypothesis which material available at home or in craft shop would work as best insulator. You can try to invent your own insulation material.
To test insulation properties you can use two plastic containers larger and smaller size. Fill the small container with ice, close it and put it in the middle of the bigger container. Fill the gap with insulation material.
Check the ice in the small container regularly. Measure the time it took the ice to fully melt. Then repeat the procedure with another insulation material. You can repeat trials for each material several times so your data are more representative.
This would make an easy and fun 7th grade science fair project. It's simple, cheap and can be compete in 24 hours.
Red cabbage indicator.
You can never tell if the liquid is acid or base only by looking on it. In chemical laboatories they measure pH with digital pH meters which is a very sensitive equipment. For rough analysis indicators are used. Indicators are chemical substances which change color depending on the pH. You might have heard about lithmus paper.
You might think, that inicators are rare chemicals, and can only be found in labs. Wrong! Many plant pigments are indicators. The purple color of red cabbage caused by substance is called anthocyanin. Antocyanins and large variety of similar pigments cause most of the color diversity in plants. Blue, yellow and red colors of flowers, fruits and autmn leaves caused by those pigments.
Anthocyanin has the ability to widely change its color depending on acid-base properties, which makes it pretty sensitive natural indicator of pH.
Red cabbage indicator is the purple pigment that can be easily extracted from the red cabbage leaves and used in further experiments to find a pH values of the liquids. Its a neat tool for your science project! Read how to make red cabbage indicator here.
Finding the Star Dust.
Approximately 10-12 billions of years ago first galaxies were formed. The stars that were formed at that time called the 1st generation stars. Some of them still live, some of them became white or red dwarf stars. Many of them ended their lives as supernovas, producing black holes or neutron stars and fertilizing our galaxy with heavy elements of periodic table, providing matter for the Earth-like planets.
Imagine that carbon, iron, calcium and other heavy elements of our bodies originate from a star that ended as a enormous blast visible from the distance of hundred millions light years.
When our Solar System was forming most of this heavy materials were absorbed by the planetoids orbiting the Sun. Planetoids became the planets but some amount of this primordial matter ejected from the old star still exists in form of the asteroids, comets and small particles. In fact every day tons of this particles collide with Earth and burn in it's thick atmosphere. Occasionally when the piece is big enough - one inch or so - you can see a brief flash of light crossing the night sky. A shooting star. It burns in the atmosphere and almost never reaches the surface. However during descent it disintegrates into smaller pieces. They brake in the atmosphere and slowly fall down as a dust. They called micrometeorites. And this is the star dust we're after.
Collecting microscopic pieces of old supernova can be a great 7th grade science fair project!
There are 2 main classes of micrometeorites - rock micrometeorites and iron micrometeorites. It's hard to isolate and distinguish rock micrometeorites from other forms of dust and debris. Iron micrometeorites are easier to collect because you can use a magnet to concentrate them.
There are many ways to collect micrometeorites. Basically the bigger area you can collect dust from the higher chances of finding micrometeorites. Time and weather may be important too. Chances of finding micrometeorites in the few days following a meteor shower are higher than after a few days of heavy rain when all the particles are washed out of atmosphere by water drops.
It's hard to collect micrometeorites if you have persistent strong winds in your area. If you just had a snowfall it's a perfect chance to find good deal of micrometeorites - snowflakes frequently form around atmospheric particles and there are chances that some of the particles will be micrometeorites. Snow is easy to collect and you can geather a lot of fresh and clean snow from a big area providing ideal conditions for a micrometeorite search.
The goal of the project:
To find, isolate and identify micrometeorites.
- A large sheet of paper or thin plastic (1-2 square meters)
- Very strong magnet.
- Strong lens, a binocular or a microscope. Having all 3 instruments is the ideal conditions for the experiment.
- When weather forecast is good, unfold the sheet of paper(plastic) outside in the open space and leave it over night.
- Collect it in the early morning when atmosphere is still and there is no wind.
- Make sure you collect it the way so that all the material deposited on the sheet can only fall to the center of the sheet.
- Wrap strong magnet in the thin plastic bag.
- "Scan" sheet with the magnet collecting all magnetic particles.
- Place magnet over the small container and gently remove magnet from the plastic bag so that all the magnetic particles fall in the container.
- Examine them with magnifying glass or microscope.
You may need to repeat this experiment several times to get enough experience and increase chances of micrometeorite finding.
As extension of this project you may try to calculate the weight of the micrometeorites falling each year on the surface of the earth.
If you didn't manage to catch any micrometeorites using this method you can try another one.